Related
I'm trying to decompile the firmware of a Logitech Freedom 2.4 Cordless Joystick. I've managed to get something of the EEPROM. (here)
The EEPROM that is used is the Microchip 25AA320, which is a 32Kbit SPI-EEPROM. The MCU is a nRF24E1G , that contains a 8051 MCU.
The ROM should be 4096 bytes, so I think that my reading program looped over it self 4 times.
I managed to extract a 4kB ROM (here), but the start of the file doesn't look clean.
I loaded both files into IDA Pro and Ghidra and selected the 8051 processor. They don't generate anything useful.
Could anyone help me decompiling this ROM?
I used this Arduino Sketch to dump the rom.
Together with this python script
## Author: Arpan Das
## Date: Fri Jan 11 12:16:59 2019 +0530
## URL: https://github.com/Cyberster/SPI-Based-EEPROM-Reader-Writer
## It listens to serial port and writes contents into a file
## requires pySerial to be installed
import sys
import serial
import time
start = time.time()
MEMORY_SIZE = 4096 # In bytes
serial_port = 'COM5'
baud_rate = 115200 # In arduino, Serial.begin(baud_rate)
write_to_file_path = "dump.rom"
output_file = open(write_to_file_path, "wb")
ser = serial.Serial(serial_port, baud_rate)
print("Press d for dump ROM else CTRL+C to exit.")
ch = sys.stdin.read(1)
if ch == 'd':
ser.write('d')
for i in range(MEMORY_SIZE/32): # i.e. MEMORY_SIZE / 32
# wait until arduino response with 'W' i.e. 1 byte of data write request
while (ser.read() != 'W'): continue
ser.write('G') # sends back write request granted signal
for j in range(32):
byte = ser.read(1);
output_file.write(byte);
print(str(MEMORY_SIZE - (i * 32)) + " bytes remaining.")
print '\nIt took', time.time()-start, ' seconds.'
This is what I did, the next part left is for you. My machine is a Win10 notebook, however I used unix tools because they are so capable.
First of all, I divided the 16KB dump into four 4KB parts. The first one was different from the other three. And the provided 4KB dump is different to all of these parts. I did not investigate this further, and simply took one of the other three parts that are all equal.
$ split -b 4K LogitechFreedom2.4CordlessJoystick.rom part
$ cmp partaa partab
partaa partab differ: byte 1, line 1
$ cmp partab partac
$ cmp partac partad
$ cmp dump.rom partaa
dump.rom partaa differ: byte 9, line 1
$ cmp dump.rom partab
dump.rom partab differ: byte 1, line 1
From the microcontroller's data sheet I learned that the EEPROM contents has a header of at least 3 bytes (chapter 10.2 at page 61).
These bytes are:
0b Version = 00, Reserved = 00, SPEED = 0.5MHz, XO_FREQ = 16MHz
03 Offset to start of user program = 3
0f Number of 256 bytes block = 15
The last entry seems to be off by one, because there seems to be code in the 16th block, too.
Anyway, these bytes look decent, so I cut the first 3 bytes.
$ dd if=partad of=rom.bin bs=1 skip=3
4093+0 records in
4093+0 records out
4093 bytes (4,1 kB, 4,0 KiB) copied, 0,0270132 s, 152 kB/s
$ dd if=partad of=head.bin bs=1 count=3
3+0 records in
3+0 records out
3 bytes copied, 0,0043809 s, 0,7 kB/s
$ od -Ax -t x1 rom.bin > rom.hex
$ od -Ax -t x1 head.bin > head.hex
The hex files are nice for loading them into an editor and look around.
I loaded the remaining 4093 bytes into a disassembler I once wrote and peeked around a bit. It looks promising, so I think you can go on without me now:
C0000: ljmp C0F54
C0003: setb 021H.2
reti
C000B: xch a,r5
inc r6
xrl a,r6
mov a,#0B2H
movc a,#a+pc
movx #r1,a
mov r7,a
setb 021H.2
reti
C0F54: mov psw,#000H
mov sp,#07BH
mov r0,#0FFH
mov #r0,#000H
djnz r0,C0F5C
ljmp C0C09
I have a doubt on the following code in TCL 8.6.8 source tclInt.h:
4277 #define TclInvalidateStringRep(objPtr) \
4278 if (objPtr->bytes != NULL) { \
4279 if (objPtr->bytes != tclEmptyStringRep) { \
4280 ckfree((char *) objPtr->bytes); \
4281 } \
4282 objPtr->bytes = NULL; \
4283 }
This macro is called by Tcl_InvalidateStringRep() in tclObj.c.
My doubt is, why doesn't tclObj's length get reset to zero?
Here is from definition of Tcl_Obj:
808 typedef struct Tcl_Obj {
809 int refCount; /* When 0 the object will be freed. */
810 char *bytes; /* This points to the first byte of the
811 * object's string representation. The array
812 * must be followed by a null byte (i.e., at
813 * offset length) but may also contain
814 * embedded null characters. The array's
815 * storage is allocated by ckalloc. NULL means
816 * the string rep is invalid and must be
817 * regenerated from the internal rep. Clients
818 * should use Tcl_GetStringFromObj or
819 * Tcl_GetString to get a pointer to the byte
820 * array as a readonly value. */
821 int length; /* The number of bytes at *bytes, not
822 * including the terminating null. */
So you can see length is tightly coupled with bytes, when bytes is cleared, shouldn't we reset length?
My doubt comes from the following code, TclCreateLiteral() in tclLiteral.c:
200 for (globalPtr=globalTablePtr->buckets[globalHash] ; globalPtr!=NULL;
201 globalPtr = globalPtr->nextPtr) {
202 objPtr = globalPtr->objPtr;
203 if ((globalPtr->nsPtr == nsPtr)
204 && (objPtr->length == length) && ((length == 0)
205 || ((objPtr->bytes[0] == bytes[0])
206 && (memcmp(objPtr->bytes, bytes, (unsigned) length) == 0)))) {
So at line 204, when length is not zero while bytes is NULL, the program crashes.
My product includes TCL source and I find the above problem when I trace a program crash. I put the workaround in our code, but like to confirm with the community if it indeed is a vulnerability.
Your aproach seems to be wrong somewhere.
The call of TclInvalidateStringRep is basically allowed for objects with no references (refCount == 0) or with exactly one reference (so refCount <= 1) and then only if you are sure, that this 1 reference is your own reference only.
Tcl's shared objects could switch its internal representation, but the string representation remains immutable. Otherwise you will break the basic principles of Tcl (like EIAS, etc).
Simplest example that can explain this:
set k 0x7f
dict set d $k test
expr {$k}; # ==> 127 (obj is integer now, but...)
puts $k; # ==> 0x7f (... still remains the string-representation)
puts [dict get $d $k]; # ==> test
# some code that fouls it up (despite of two references var `k` and key in dict `d`):
magic_happens_here $k; # string representation gets lost.
# and hereafter:
puts $k; # ==> 127 (representation is now 127, so...)
puts [dict get $d $k]; # ==> ERROR: key "127" not known in dictionary
As you can see, reset resp. altering of the string representation of shared object is wrong by design.
Please avoid this in Tcl.
I've had a think about this, and while I believe that the code that is purging the representation is wrong to do so (since the object should in principle be shared and so shouldn't be observed to change) I certainly think that it is extremely difficult to actually prove that that can't happen. For sure, TclCreateLiteral in tclLiteral.c shouldn't blow up if it happens!
The fix I'm using is to make TclCreateLiteral use TclGetStringFromObj (the Tcl-internal macro-ized version of Tcl_GetStringFromObj) to get the bytes and length fields instead of using them directly, so that the correct constraints are preserved. This should make the string representation exist once more if it is removed. If the code continues to crash, the problem is your code that is calling TclInvalidateStringRep on a literal (and setting a type that can't have a string generated for it; Tcl has some of those, but that's because it never purges the original string from them).
Remember, a Tcl_Obj should only have its string rep purged when it becomes wrong, not just when it gains a non-string representation. The fact a value has been interpreted as an integer doesn't mean that it shouldn't be interpretable as a list (quite the reverse!) and if the internal representation is never updated to a different value (in-place modifications should only ever happen to unshared objects) it should never need to lose that string representation at all.
Locked. This question and its answers are locked because the question is off-topic but has historical significance. It is not currently accepting new answers or interactions.
Challenge
The shortest program by character count that accepts standard input of the form X-Y R, with the following guarantees:
R is a non-negative decimal number less than or equal to 8
X and Y are non-negative angles given in decimal as multiples of 45° (0, 45, 90, 135, etc.)
X is less than Y
Y is not 360 if X is 0
And produces on standard output an ASCII "arc" from the starting angle X to the ending angle Y of radius R, where:
The vertex of the arc is represented by o
Angles of 0 and 180 are represented by -
Angles of 45 and 225 are represented by /
Angles of 90 and 270 are represented by |
Angles of 135 and 315 are represented by \
The polygonal area enclosed by the two lines is filled with a non-whitespace character.
The program is not required to produce meaningful output if given invalid input. Solutions in any language are allowed, except of course a language written specifically for this challenge, or one that makes unfair use of an external utility. Extraneous horizontal and vertical whitespace is allowed in the output provided that the format of the output remains correct.
Happy golfing!
Numerous Examples
Input:
0-45 8
Output:
/
/x
/xx
/xxx
/xxxx
/xxxxx
/xxxxxx
/xxxxxxx
o--------
Input:
0-135 4
Output:
\xxxxxxxx
\xxxxxxx
\xxxxxx
\xxxxx
o----
Input:
180-360 2
Output:
--o--
xxxxx
xxxxx
Input:
45-90 0
Output:
o
Input:
0-315 2
Output:
xxxxx
xxxxx
xxo--
xxx\
xxxx\
Perl, 235 211 225 211 207 196 179 177 175 168 160 156 146 chars
<>=~/-\d+/;for$y(#a=-$'..$'){print+(map$_|$y?!($t=8*($y>0)+atan2(-$y,$_)/atan2 1,1)&-$&/45==8|$t>=$`/45&$t<=-$&/45?qw(- / | \\)[$t%4]:$":o,#a),$/}
Perl using say feature, 161 149 139 chars
$ echo -n '<>=~/-\d+/;for$y(#a=-$'"'"'..$'"'"'){say map$_|$y?!($t=8*($y>0)+atan2(-$y,$_)/atan2 1,1)&-$&/45==8|$t>=$`/45&$t<=-$&/45?qw(- / | \\)[$t%4]:$":o,#a}' | wc -c
139
$ perl -E '<>=~/-\d+/;for$y(#a=-$'"'"'..$'"'"'){say map$_|$y?!($t=8*($y>0)+atan2(-$y,$_)/atan2 1,1)&-$&/45==8|$t>=$`/45&$t<=-$&/45?qw(- / | \\)[$t%4]:$":o,#a}'
Perl without trailing newline, 153 143 chars
<>=~/-\d+/;for$y(#a=-$'..$'){print$/,map$_|$y?!($t=8*($y>0)+atan2(-$y,$_)/atan2 1,1)&-$&/45==8|$t>=$`/45&$t<=-$&/45?qw(- / | \\)[$t%4]:$":o,#a}
Original version commented:
$_=<>;m/(\d+)-(\d+) (\d+)/;$e=$1/45;$f=$2/45; # parse angles and radius, angles are 0-8
for$y(-$3..$3){ # loop for each row and col
for$x(-$3..$3){
$t=atan2(-$y,$x)/atan2 1,1; # angle of this point
$t+=8if($t<0); # normalize negative angles
#w=split//,"-/|\\"x2; # array of ASCII symbols for enclosing lines
$s.=!$x&&!$y?"o":$t==$e||$t==$f?$w[$t]:$t>$e&&$t<$f?"x":$";
# if it's origin -> "o", if it's enclosing line, get symbol from array
# if it's between enclosing angles "x", otherwise space
}
$s.=$/;
}
print$s;
EDIT 1: Inlined sub, relational and equality operators return 0 or 1.
EDIT 2: Added version with comments.
EDIT 3: Fixed enclosing line at 360º. Char count increased significantly.
EDIT 4: Added a shorter version, bending the rules.
EDIT 5: Smarter fix for the 360º enclosing line. Also, use a number as fill. Both things were obvious. Meh, I should sleep more :/
EDIT 6: Removed unneeded m from match operator. Removed some semicolons.
EDIT 7: Smarter regexp. Under 200 chars!
EDIT 8: Lots of small improvements:
Inner for loop -> map (1 char)
symbol array from split string -> qw (3 chars)
inlined symbol array (6 chars, together with the previous improvement 9 chars!)
Logical or -> bitwise or (1 char)
Regexp improvement (1 char)
Use arithmethic for testing negative angles, inspired by Jacob's answer (5 chars)
EDIT 9: A little reordering in the conditional operators saves 2 chars.
EDIT 10: Use barewords for characters.
EDIT 11: Moved print inside of loop, inspired by Lowjacker's answer.
EDIT 12: Added version using say.
EDIT 13: Reuse angles characters for fill character, as Gwell's answer does. Output isn't as nice as Gwell's though, that would require 5 additional chars :) Also, .. operator doen't need parentheses.
EDIT 14: Apply regex directly to <>. Assign range operator to a variable, as per Adrian's suggestion to bta's answer. Add version without the final newline. Updated say version.
EDIT 15: More inlining. map{block}#a -> map expr,#a.
Lua, 259 characters
Slightly abuses the non-whitespace character clause to produce a dazzling display and more importantly save strokes.
m=math i=io.read():gmatch("%d+")a=i()/45 b=i()/45 r=i()for y=r,-r,-1 do for x=-r,r do c=m.atan2(y,x)/m.pi*4 c=c<0 and c+8 or c k=1+m.modf(c+.5)io.write(x==0 and y==0 and'o'or c>=a and c<=b and('-/|\\-/|\\-'):sub(k,k)or c==0 and b==8 and'-'or' ')end print()end
Input: 45-360 4
\\\|||///
\\\|||//
\\\\|//
--\\|/
----o----
--//|\\--
////|\\\\
///|||\\\
///|||\\\
Able to handle odd angles
Input: 15-75 8
|/////
|//////
|//////
|//////
///////
|//////-
////---
//-
o
MATLAB, 188 chars :)
input '';[w x r]=strread(ans,'%d-%d%d');l='-/|\-/|\-';[X Y]=meshgrid(-r:r);T=atan2(-Y,X)/pi*180;T=T+(T<=0)*360;T(T>w&T<x)=-42;T(T==w)=-l(1+w/45);T(T==x)=-l(1+x/45);T(r+1,r+1)=-'o';char(-T)
Commented code:
%%# Get the string variable (enclose in quotes, e.g. '45-315 4')
input ''
%%# Extract angles and length
[w x r]=strread(ans,'%d-%d%d');
%%# Store characters
l='-/|\-/|\-';
%%# Create the grid
[X Y]=meshgrid(-r:r);
%%# Compute the angles in degrees
T=atan2(-Y,X)/pi*180;
%%# Get all the angles
T=T+(T<=0)*360;
%# Negative numbers indicate valid characters
%%# Add the characters
T(T>w&T<x)=-42;
T(T==w)=-l(1+w/45);
T(T==x)=-l(1+x/45);
%%# Add the origin
T(r+1,r+1)=-'o';
%%# Display
char(-T)
Mathematica 100 Chars
Out of competition because graphics are too perfect :)
f[x_-y_ z_]:=Graphics#Table[
{EdgeForm#Red,Disk[{0,0},r,{x °,y °}],{r,z,1,-1}]
SetAttributes[f,HoldAll]
Invoke with
f[30-70 5]
Result
alt text http://a.imageshack.us/img80/4294/angulosgolf.png
alt text http://a.imageshack.us/img59/7892/angulos2.png
Note
The
SetAttributes[f, HoldAll];
is needed because the input
f[a-b c]
is otherwise interpreted as
f[(a-b*c)]
GNU BC, 339 chars
Gnu bc because of read(), else and logical operators.
scale=A
a=read()/45
b=read()/45
c=read()
for(y=c;y>=-c;y--){for(x=-c;x<=c;x++){if(x==0)if(y<0)t=-2else t=2else if(x>0)t=a(y/x)/a(1)else if(y<0)t=a(y/x)/a(1)-4else t=a(y/x)/a(1)+4
if(y<0)t+=8
if(x||y)if(t==a||t==b||t==b-8){scale=0;u=(t%4);scale=A;if(u==0)"-";if(u==1)"/";if(u==2)"|";if(u==3)"\"}else if(t>a&&t<b)"x"else" "else"o"};"
"}
quit
MATLAB 7.8.0 (R2009a) - 168 163 162 characters
Starting from Jacob's answer and inspired by gwell's use of any non-whitespace character to fill the arc, I managed the following solution:
[w x r]=strread(input('','s'),'%d-%d%d');
l='o -/|\-/|\-';
X=meshgrid(-r:r);
T=atan2(-X',X)*180/pi;
T=T+(T<=-~w)*360;
T(T>x|T<w)=-1;
T(r+1,r+1)=-90;
disp(l(fix(3+T/45)))
And some test output:
>> arc
0-135 4
\||||////
\|||///-
\||//--
\|/---
o----
I could reduce it further to 156 characters by removing the call to disp, but this would add an extra ans = preceding the output (which might violate the output formatting rules).
Even still, I feel like there are some ways to reduce this further. ;)
Ruby, 292 276 186 chars
x,y,r=gets.scan(/\d+/).map{|z|z.to_i};s=(-r..r);s.each{|a|s.each{|b|g=Math::atan2(-a,b)/Math::PI*180/1%360;print a|b==0?'o':g==x||g==y%360?'-/|\\'[g/45%4].chr: (x..y)===g ?'*':' '};puts}
Nicer-formatted version:
x, y, r = gets.scan(/\d+/).map{|z| z.to_i}
s = (-r..r)
s.each {|a|
s.each {|b|
g = (((Math::atan2(-a,b) / Math::PI) * 180) / 1) % 360
print ((a | b) == 0) ? 'o' :
(g == x || g == (y % 360)) ? '-/|\\'[(g / 45) % 4].chr :
((x..y) === g) ? '*' : ' '
}
puts
}
I'm sure someone out there who got more sleep than I did can condense this more...
Edit 1: Switched if statements in inner loop to nested ? : operator
Edit 2: Stored range to intermediate variable (thanks Adrian), used stdin instead of CLI params (thanks for the clarification Jon), eliminated array in favor of direct output, fixed bug where an ending angle of 360 wouldn't display a line, removed some un-needed parentheses, used division for rounding instead of .round, used modulo instead of conditional add
Ruby, 168 characters
Requires Ruby 1.9 to work
s,e,r=gets.scan(/\d+/).map &:to_i;s/=45;e/=45;G=-r..r;G.map{|y|G.map{|x|a=Math.atan2(-y,x)/Math::PI*4%8;print x|y!=0?a==s||a==e%8?'-/|\\'[a%4]:a<s||a>e ?' ':8:?o};puts}
Readable version:
start, _end, radius = gets.scan(/\d+/).map &:to_i
start /= 45
_end /= 45
(-radius..radius).each {|y|
(-radius..radius).each {|x|
angle = Math.atan2(-y, x)/Math::PI * 4 % 8
print x|y != 0 ? angle==start || angle==_end%8 ? '-/|\\'[angle%4] : angle<start || angle>_end ? ' ' : 8 : ?o
}
puts
}
Perl - 388 characters
Since it wouldn't be fair to pose a challenge I couldn't solve myself, here's a solution that uses string substitution instead of trigonometric functions, and making heavy use of your friendly neighbourhood Perl's ability to treat barewords as strings. It's necessarily a little long, but perhaps interesting for the sake of uniqueness:
($x,$y,$r)=split/\D/,<>;for(0..$r-1){$t=$r-1-$_;
$a.=L x$_.D.K x$t.C.J x$t.B.I x$_."\n";
$b.=M x$t.F.N x$_.G.O x$_.H.P x$t."\n"}
$_=$a.E x$r.o.A x$r."\n".$b;$x/=45;$y/=45;$S=' ';
sub A{$v=$_[0];$x==$v||$y==$v?$_[1]:$x<$v&&$y>$v?x:$S}
sub B{$x<=$_[0]&&$y>$_[0]?x:$S}
#a=!$x||$y==8?'-':$S;
push#a,map{A$_,'\\'.qw(- / | \\)[$_%4]}1..7;
push#a,!$x?x:$S,map{B$_}1..7;
eval"y/A-P/".(join'',#a)."/";print
All newlines are optional. It's fairly straightforward:
Grab user input.
Build the top ($a) and bottom ($b) parts of the pattern.
Build the complete pattern ($_).
Define a sub A to get the fill character for an angle.
Define a sub B to get the fill character for a region.
Build an array (#a) of substitution characters using A and B.
Perform the substitution and print the results.
The generated format looks like this, for R = 4:
DKKKCJJJB
LDKKCJJBI
LLDKCJBII
LLLDCBIII
EEEEoAAAA
MMMFGHPPP
MMFNGOHPP
MFNNGOOHP
FNNNGOOOH
Where A-H denote angles and I-P denote regions.
(Admittedly, this could probably be golfed further. The operations on #a gave me incorrect output when written as one list, presumably having something to do with how map plays with $_.)
C# - 325 319 chars
using System;class P{static void Main(){var s=Console.ReadLine().Split(' ');
var d=s[0].Split('-');int l=s[1][0]-48,x,y,r,a=int.Parse(d[0]),b=int.Parse(d[1]);
for(y=l;y>=-l;y--)for(x=-l;x<=l;)Console.Write((x==0&&y==0?'o':a<=(r=((int)
(Math.Atan2(y,x)*57.3)+360)%360)&&r<b||r==b%360?
#"-/|\"[r/45%4]:' ')+(x++==l?"\n":""));}}
Newlines not significant.
Sample input/output
45-180 8
\||||||||////////
\\|||||||///////
\\\||||||//////
\\\\|||||/////
\\\\\||||////
\\\\\\|||///
\\\\\\\||//
\\\\\\\\|/
--------o
135-360 5
\
\\
\\\
\\\\
\\\\\
-----o-----
----/|\\\\\
---//||\\\\
--///|||\\\
-////||||\\
/////|||||\
Java - 304 chars
class A{public static void main(String[]a){String[]b=a[0].split("-");int e=new Integer(b[1]),r=new Integer(a[1]),g,x,y=r;for(;y>=-r;y--)for(x=-r;x<=r;)System.out.print((x==0&y==0?'o':new Integer(b[0])<=(g=((int)(Math.atan2(y,x)*57.3)+360)%360)&g<e|g==e%360?"-/|\\".charAt(g/45%4):' ')+(x++<r?"":"\n"));}}
More readable version:
class A{
public static void main(String[]a){
String[]b=a[0].split("-");
int e=new Integer(b[1]),r=new Integer(a[1]),g,x,y=r;
for(;y>=-r;y--)for(x=-r;x<=r;)System.out.print((
x==0&y==0
?'o'
:new Integer(b[0])<=(g=((int)(Math.atan2(y,x)*57.3)+360)%360)&g<e|g==e%360
?"-/|\\".charAt(g/45%4)
:' '
)+(x++<r?"":"\n"));
}
}
C (902 byte)
This doesn't use trigonometric functions (like the original perl version), so it's quite ``bloated''. Anyway, here is my first code-golf submission:
#define V(r) (4*r*r+6*r+3)
#define F for(i=0;i<r;i++)
#define C ;break;case
#define U p-=2*r+2,
#define D p+=2*r+2,
#define R *++p=
#define L *--p=
#define H *p='|';
#define E else if
#define G(a) for(j=0;j<V(r)-1;j++)if(f[j]==i+'0')f[j]=a;
#define O(i) for(i=0;i<2*r+1;i++){
main(int i,char**v){char*p,f[V(8)];
int j,m,e,s,x,y,r;p=*++v;x=atoi(p);while(*p!=45)p++;
char*h="0123";y=atoi(p+1);r=atoi(*++v);
for(p=f+2*r+1;p<f+V(r);p+=2*r+2)*p=10;
*(p-2*r-2)=0;x=x?x/45:x;y/=45;s=0;e=2*r;m=r;p=f;O(i)O(j)
if(j>e)*p=h[0];E(j>m)*p=h[1];E(j>s)*p=h[2];else*p=h[3];p++;}
if(i+1==r){h="7654";m--;e--;}E(i==r){s--;}E(i>r){s--;e++;}
else{s++;e--;}p++;}for(p=f+V(r)/2-1,i=0;i<r;i++)*++p=48;
for(i=0;i<8;i++)if(i>=x&&i<y){G(64);}else G(32);
y=y==8?0:y;q:p=f+V(r)/2-1;*p='o';switch(x){
C 0:F R 45 C 1:F U R 47 C 2:F U H C 3:F U L 92
C 4:F L 45 C 5:F D L 47 C 6:F D H C 7:F D R 92;}
if(y!=8){x=y;y=8;goto q;}puts(f);}
also, the #defines look rather ugly, but they save about 200 bytes so I kept them in, anyway. It is valid ANSI C89/C90 and compiles with very few warnings (two about atoi and puts and two about crippled form of main).
Locked. This question and its answers are locked because the question is off-topic but has historical significance. It is not currently accepting new answers or interactions.
The Challenge
Guidelines for code-golf on SO
The shortest code by character count to display a representation of a circle of radius R using the *character, followed by an approximation of π.
Input is a single number, R.
Since most computers seem to have almost 2:1 ratio you should only output lines where y is odd. This means that when R is odd you should print R-1 lines. There is a new testcase for R=13 to clarify.
eg.
Input
5
Output Correct Incorrect
3 ******* 4 *******
1 ********* 2 *********
-1 ********* 0 ***********
-3 ******* -2 *********
2.56 -4 *******
3.44
Edit: Due to widespread confusion caused by odd values of R, any solutions that pass the 4 test cases given below will be accepted
The approximation of π is given by dividing twice the number of * characters by R².
The approximation should be correct to at least 6 significant digits.
Leading or trailing zeros are permitted, so for example any of 3, 3.000000, 003 is accepted for the inputs of 2 and 4.
Code count includes input/output (i.e., full program).
Test Cases
Input
2
Output
***
***
3.0
Input
4
Output
*****
*******
*******
*****
3.0
Input
8
Output
*******
*************
***************
***************
***************
***************
*************
*******
3.125
Input
10
Output
*********
***************
*****************
*******************
*******************
*******************
*******************
*****************
***************
*********
3.16
Bonus Test Case
Input
13
Output
*************
*******************
*********************
***********************
*************************
*************************
*************************
*************************
***********************
*********************
*******************
*************
2.98224852071
C: 131 chars
(Based on the C++ solution by Joey)
main(i,j,c,n){for(scanf("%d",&n),c=0,i|=-n;i<n;puts(""),i+=2)for(j=-n;++j<n;putchar(i*i+j*j<n*n?c++,42:32));printf("%g",2.*c/n/n);}
(Change the i|=-n to i-=n to remove the support of odd number cases. This merely reduces char count to 130.)
As a circle:
main(i,j,
c,n){for(scanf(
"%d",&n),c=0,i=1|
-n;i<n;puts(""),i+=
0x2)for(j=-n;++j<n;
putchar(i*i+j*j<n*n
?c++,0x02a:0x020));
printf("%g",2.*c/
n/n);3.1415926;
5358979;}
XSLT 1.0
Just for fun, here's an XSLT version. Not really code-golf material, but it solves the problem in a weird-functional-XSLT-kind of way :)
<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt" >
<xsl:output method="html"/>
<!-- Skip even lines -->
<xsl:template match="s[#y mod 2=0]">
<xsl:variable name="next">
<!-- Just go to next line.-->
<s R="{#R}" y="{#y+1}" x="{-#R}" area="{#area}"/>
</xsl:variable>
<xsl:apply-templates select="msxsl:node-set($next)"/>
</xsl:template>
<!-- End of the line?-->
<xsl:template match="s[#x > #R]">
<xsl:variable name="next">
<!-- Go to next line.-->
<s R="{#R}" y="{#y+1}" x="{-#R}" area="{#area}"/>
</xsl:variable><!-- Print LF-->
<xsl:apply-templates
select="msxsl:node-set($next)"/>
</xsl:template>
<!-- Are we done? -->
<xsl:template match="s[#y > #R]">
<!-- Print PI approximation -->
<xsl:value-of select="2*#area div #R div #R"/>
</xsl:template>
<!-- Everything not matched above -->
<xsl:template match="s">
<!-- Inside the circle?-->
<xsl:variable name="inside" select="#x*#x+#y*#y < #R*#R"/>
<!-- Print "*" or " "-->
<xsl:choose>
<xsl:when test="$inside">*</xsl:when>
<xsl:otherwise> </xsl:otherwise>
</xsl:choose>
<xsl:variable name="next">
<!-- Add 1 to area if we're inside the circle. Go to next column.-->
<s R="{#R}" y="{#y}" x="{#x+1}" area="{#area+number($inside)}"/>
</xsl:variable>
<xsl:apply-templates select="msxsl:node-set($next)"/>
</xsl:template>
<!-- Begin here -->
<xsl:template match="/R">
<xsl:variable name="initial">
<!-- Initial state-->
<s R="{number()}" y="{-number()}" x="{-number()}" area="0"/>
</xsl:variable>
<pre>
<xsl:apply-templates select="msxsl:node-set($initial)"/>
</pre>
</xsl:template>
</xsl:stylesheet>
If you want to test it, save it as pi.xslt and open the following XML file in IE:
<?xml version="1.0"?>
<?xml-stylesheet href="pi.xslt" type="text/xsl" ?>
<R>
10
</R>
Perl, 95 96 99 106 109 110 119 characters:
$t+=$;=1|2*sqrt($r**2-($u-2*$_)**2),say$"x($r-$;/2).'*'x$;for 0..
($u=($r=<>)-1|1);say$t*2/$r**2
(The newline can be removed and is only there to avoid a scrollbar)
Yay! Circle version!
$t+=$;=
1|2*sqrt($r**
2-($u-2*$_)**2)
,say$"x($r-$;/2
).'*'x$;for 0..
($u=($r=<>)-1|1
);$pi=~say$t*
2/$r**2
For the uninitiated, the long version:
#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';
# Read the radius from STDIN
my $radius = <>;
# Since we're only printing asterisks on lines where y is odd,
# the number of lines to be printed equals the size of the radius,
# or (radius + 1) if the radius is an odd number.
# Note: we're always printing an even number of lines.
my $maxline = ($radius - 1) | 1;
my $surface = 0;
# for ($_ = 0; $_ <= $maxline; $_++), if you wish
for (0 .. $maxline) {
# First turn 0 ... N-1 into -(N/2) ... N/2 (= Y-coordinates),
my $y = $maxline - 2*$_;
# then use Pythagoras to see how many stars we need to print for this line.
# Bitwise OR "casts" to int; and: 1 | int(2 * x) == 1 + 2 * int(x)
my $stars = 1 | 2 * sqrt($radius**2-$y**2);
$surface += $stars;
# $" = $LIST_SEPARATOR: default is a space,
# Print indentation + stars
# (newline is printed automatically by say)
say $" x ($radius - $stars/2) . '*' x $stars;
}
# Approximation of Pi based on surface area of circle:
say $surface*2/$radius**2;
FORTRAN - 101 Chars
$ f95 piday.f95 -o piday && echo 8 | ./piday
READ*,N
DO I=-N,N,2
M=(N*N-I*I)**.5
PRINT*,(' ',J=1,N-M),('*',J=0,M*2)
T=T+2*J
ENDDO
PRINT*,T/N/N
END
READ*,N
K=N/2*2;DO&
I=1-K,N,2;M=&
(N*N-I*I)**.5;;
PRINT*,(' ',J=&
1,N-M),('*',J=&
0,M*2);T=T+2*J;
ENDDO;PRINT*&
,T/N/N;END;
!PI-DAY
x86 Machine Code: 127 bytes
Intel Assembler: 490 chars
mov si,80h
mov cl,[si]
jcxz ret
mov bx,10
xor ax,ax
xor bp,bp
dec cx
a:mul bx
mov dl,[si+2]
sub dl,48
cmp dl,bl
jae ret
add ax,dx
inc si
loop a
mov dl,al
inc dl
mov dh,al
add dh,dh
mov ch,dh
mul al
mov di,ax
x:mov al,ch
sub al,dl
imul al
mov si,ax
mov cl,dh
c:mov al,cl
sub al,dl
imul al
add ax,si
cmp ax,di
mov al,32
ja y
or al,bl
add bp,2
y:int 29h
dec cl
jnz c
mov al,bl
int 29h
mov al,13
int 29h
sub ch,2
jnc x
mov ax,bp
cwd
mov cl,7
e:div di
cmp cl,6
jne z
pusha
mov al,46
int 29h
popa
z:add al,48
int 29h
mov ax,bx
mul dx
jz ret
dec cl
jnz e
ret
This version handles the bonus test case as well and is 133 bytes:
mov si,80h
mov cl,[si]
jcxz ret
mov bx,10
xor ax,ax
xor bp,bp
dec cx
a:mul bx
mov dl,[si+2]
sub dl,48
cmp dl,bl
jae ret
add ax,dx
inc si
loop a
mov dl,al
rcr dl,1
adc dl,dh
add dl,dl
mov dh,dl
add dh,dh
dec dh
mov ch,dh
mul al
mov di,ax
x:mov al,ch
sub al,dl
imul al
mov si,ax
mov cl,dh
c:mov al,cl
sub al,dl
imul al
add ax,si
cmp ax,di
mov al,32
jae y
or al,bl
add bp,2
y:int 29h
dec cl
jnz c
mov al,bl
int 29h
mov al,13
int 29h
sub ch,2
jnc x
mov ax,bp
cwd
mov cl,7
e:div di
cmp cl,6
jne z
pusha
mov al,46
int 29h
popa
z:add al,48
int 29h
mov ax,bx
mul dx
jz ret
dec cl
jnz e
ret
Python: 101 104 107 110 chars
Based on the other Python version by Nicholas Riley.
r=input()
t=0
i=1
exec"n=1+int((2*i*r-i*i)**.5)*2;t+=2.*n/r/r;print' '*(r-n/2)+'*'*n;i+=2;"*r
print t
Credits to AlcariTheMad for some of the math.
Ah, the odd-numbered ones are indexed with zero as the middle, explains everything.
Bonus Python: 115 chars (quickly hacked together)
r=input()
t=0
i=1
while i<r*2:n=1+int((2*i*r-i*i)**.5)*2;t+=2.*n/r/r;print' '*(r-n/2)+'*'*n;i+=2+(r-i==2)*2
print t
In dc: 88 and 93 93 94 96 102 105 129 138 141 chars
Just in case, I am using OpenBSD and some supposedly non-portable extensions at this point.
93 chars. This is based on same formula as FORTRAN solution (slightly different results than test cases). Calculates X^2=R^2-Y^2 for every Y
[rdPr1-d0<p]sp1?dsMdd*sRd2%--
[dd*lRr-vddlMr-32rlpxRR42r2*lpxRRAP4*2+lN+sN2+dlM>y]
dsyx5klNlR/p
88 chars. Iterative solution. Matches test cases. For every X and Y checks if X^2+Y^2<=R^2
1?dsMdd*sRd2%--sY[0lM-[dd*lYd*+lRr(2*d5*32+PlN+sN1+dlM!<x]dsxxAPlY2+dsYlM>y]
dsyx5klNlR/p
To run dc pi.dc.
Here is an older annotated version:
# Routines to print '*' or ' '. If '*', increase the counter by 2
[lN2+sN42P]s1
[32P]s2
# do 1 row
# keeping I in the stack
[
# X in the stack
# Calculate X^2+Y^2 (leave a copy of X)
dd*lYd*+
#Calculate X^2+Y^2-R^2...
lR-d
# .. if <0, execute routine 1 (print '*')
0>1
# .. else execute routine 2 (print ' ')
0!>2
# increment X..
1+
# and check if done with line (if not done, recurse)
d lM!<x
]sx
# Routine to cycle for the columns
# Y is on the stack
[
# push -X
0lM-
# Do row
lxx
# Print EOL
10P
# Increment Y and save it, leaving 2 copies
lY 2+ dsY
# Check for stop condition
lM >y
]sy
# main loop
# Push Input value
[Input:]n?
# Initialize registers
# M=rows
d sM
# Y=1-(M-(M%2))
dd2%-1r-sY
# R=M^2
d*sR
# N=0
0sN
[Output:]p
# Main routine
lyx
# Print value of PI, N/R
5klNlR/p
Powershell, 119 113 109 characters
($z=-($n=$args[($s=0)])..$n)|?{$_%2}|%{$l="";$i=$_
$z|%{$l+=" *"[$i*$i+$_*$_-lt$n*$n-and++$s]};$l};2*$s/$n/$n
and here's a prettier version:
( $range = -( $R = $args[ ( $area = 0 ) ] ) .. $R ) |
where { $_ % 2 } |
foreach {
$line = ""
$i = $_
$range | foreach {
$line += " *"[ $i*$i + $_*$_ -lt $R*$R -and ++$area ]
}
$line
}
2 * $area / $R / $R
HyperTalk: 237 characters
Indentation is not required nor counted. It is added for clarity. Also note that HyperCard 2.2 does accept those non-ASCII relational operators I used.
function P R
put""into t
put 0into c
repeat with i=-R to R
if i mod 2≠0then
repeat with j=-R to R
if i^2+j^2≤R^2then
put"*"after t
add 1to c
else
put" "after t
end if
end repeat
put return after t
end if
end repeat
return t&2*c/R/R
end P
Since HyperCard 2.2 doesn't support stdin/stdout, a function is provided instead.
C#: 209 202 201 characters:
using C=System.Console;class P{static void Main(string[]a){int r=int.Parse(a[0]),s=0,i,x,y;for(y=1-r;y<r;y+=2){for(x=1-r;x<r;s+=i)C.Write(" *"[i=x*x+++y*y<=r*r?1:0]);C.WriteLine();}C.Write(s*2d/r/r);}}
Unminified:
using C = System.Console;
class P {
static void Main(string[] arg) {
int r = int.Parse(arg[0]), sum = 0, inside, x, y;
for (y = 1 - r; y < r; y += 2) {
for (x = 1 - r; x < r; sum += inside)
C.Write(" *"[inside = x * x++ + y * y <= r * r ? 1 : 0]);
C.WriteLine();
}
C.Write(sum * 2d / r / r);
}
}
Haskell 139 145 147 150 230 chars:
x True=' ';x _='*'
a n=unlines[[x$i^2+j^2>n^2|j<-[-n..n]]|i<-[1-n,3-n..n]]
b n=a n++show(sum[2|i<-a n,i=='*']/n/n)
main=readLn>>=putStrLn.b
Handling the odd numbers: 148 chars:
main=do{n<-readLn;let{z k|k<n^2='*';z _=' ';c=[[z$i^2+j^2|j<-[-n..n]]|i<-[1,3..n]];d=unlines$reverse c++c};putStrLn$d++show(sum[2|i<-d,i=='*']/n/n)}
150 chars:
(Based on the C version.)
a n=unlines[concat[if i^2+j^2>n^2then" "else"*"|j<-[-n..n]]|i<-[1-n,3-n..n]]
main=do n<-read`fmap`getLine;putStr$a n;print$2*sum[1|i<-a n,i=='*']/n/n
230 chars:
main=do{r<-read`fmap`getLine;let{p=putStr;d=2/fromIntegral r^2;l y n=let c m x=if x>r then p"\n">>return m else if x*x+y*y<r*r then p"*">>c(m+d)(x+1)else p" ">>c m(x+1)in if y>r then print n else c n(-r)>>=l(y+2)};l(1-r`mod`2-r)0}
Unminified:
main = do r <- read `fmap` getLine
let p = putStr
d = 2/fromIntegral r^2
l y n = let c m x = if x > r
then p "\n" >> return m
else if x*x+y*y<r*r
then p "*" >> c (m+d) (x+1)
else p " " >> c m (x+1)
in if y > r
then print n
else c n (-r) >>= l (y+2)
l (1-r`mod`2-r) 0
I was kinda hoping it would beat some of the imperative versions, but I can't seem to compress it any further at this point.
Ruby, 96 chars
(based on Guffa's C# solution):
r=gets.to_f
s=2*t=r*r
g=1-r..r
g.step(2){|y|g.step{|x|putc' * '[i=t<=>x*x+y*y];s+=i}
puts}
p s/t
109 chars (bonus):
r=gets.to_i
g=-r..r
s=g.map{|i|(g.map{|j|i*i+j*j<r*r ?'*':' '}*''+"\n")*(i%2)}*''
puts s,2.0/r/r*s.count('*')
PHP: 117
Based on dev-null-dweller
for($y=1-$r=$argv[1];$y<$r;$y+=2,print"\n")for($x=1-$r;$x<$r;$x++)echo$r*$r>$x*$x+$y*$y&&$s++?'*':' ';echo$s*2/$r/$r;
You guys are thinking way too hard.
switch (r) {
case 1,2:
echo "*"; break;
case 3,4:
echo " ***\n*****\n ***"; break;
// etc.
}
J: 47, 46, 45
Same basic idea as other solutions, i.e. r^2 <= x^2 + y^2, but J's array-oriented notation simplifies the expression:
c=:({&' *',&":2*+/#,%#*#)#:>_2{.\|#j./~#i:#<:
You'd call it like c 2 or c 8 or c 10 etc.
Bonus: 49
To handle odd input, e.g. 13, we have to filter on odd-valued x coordinates, rather than simply taking every other row of output (because now the indices could start at either an even or odd number). This generalization costs us 4 characters:
c=:*:({&' *'#],&":2%(%+/#,))]>(|#j./~2&|#])#i:#<:
Deminimized version:
c =: verb define
pythag =. y > | j./~ i:y-1 NB. r^2 > x^2 + y^2
squished =. _2 {.\ pythag NB. Odd rows only
piApx =. (2 * +/ , squished) % y*y
(squished { ' *') , ": piApx
)
Improvements and generalizations due to Marshall Lochbam on the J Forums.
Python: 118 characters
Pretty much a straightforward port of the Perl version.
r=input()
u=r+r%2
t=0
for i in range(u):n=1+2*int((r*r-(u-1-2*i)**2)**.5);t+=n;print' '*(r-n/2-1),'*'*n
print 2.*t/r/r
C++: 169 characters
#include <iostream>
int main(){int i,j,c=0,n;std::cin>>n;for(i=-n;i<=n;i+=2,std::cout<<'\n')for(j=-n;j<=n;j++)std::cout<<(i*i+j*j<=n*n?c++,'*':' ');std::cout<<2.*c/n/n;}
Unminified:
#include <iostream>
int main()
{
int i,j,c=0,n;
std::cin>>n;
for(i=-n;i<=n;i+=2,std::cout<<'\n')
for(j=-n;j<=n;j++)
std::cout<<(i*i+j*j<=n*n?c++,'*':' ');
std::cout<<2.*c/n/n;
}
(Yes, using std:: instead of using namespace std uses less characters)
The output here doesn't match the test cases in the original post, so here's one that does (written for readability). Consider it a reference implementation (if Poita_ doesn't mind):
#include <iostream>
using namespace std;
int main()
{
int i, j, c=0, n;
cin >> n;
for(i=-n; i<=n; i++) {
if (i & 1) {
for(j=-n; j<=n; j++) {
if (i*i + j*j <= n*n) {
cout << '*';
c++;
} else {
cout << ' ';
}
}
cout << '\n';
}
}
cout << 2.0 * c / n / n << '\n';
}
C++: 168 characters (with output I believe is correct)
#include <iostream>
int main(){int i,j,c=0,n;std::cin>>n;for(i=-n|1;i<=n;i+=2,std::cout<<"\n")for(j=-n;j<=n;j++)std::cout<<" *"[i*i+j*j<=n*n&&++c];std::cout<<2.*c/n/n;}
PHP: 126 132 138
(based on Guffa C# solution)
126:
for($y=1-($r=$argv[1]);$y<$r;$y+=2,print"\n")for($x=1-$r;$x<$r;$s+=$i,++$x)echo($i=$x*$x+$y*$y<=$r*$r)?'*':' ';echo$s*2/$r/$r;
132:
for($y=1-($r=$argv[1]);$y<$r;$y+=2){for($x=1-$r;$x<$r;#$s+=$i,++$x)echo($i=$x*$x+$y*$y<=$r*$r?1:0)?'*':' ';echo"\n";}echo$s*2/$r/$r;
138:
for($y=1-($r=$argv[1]);$y<$r;$y+=2){for($x=1-$r;$x<$r;#$s+=$i){$t=$x;echo($i=$t*$x++ +$y*$y<=$r*$r?1:0)?'*':' ';}echo"\n";}echo$s*2/$r/$r;
Current full:
for( $y = 1 - ( $r = $argv[1]); $y < $r; $y += 2, print "\n")
for( $x = 1-$r; $x < $r; $s += $i, ++$x)
echo( $i = $x*$x + $y*$y <= $r*$r) ? '*' : ' ';
echo $s*2 /$r /$r;
Can be without # before first $s but only with error_reporting set to 0 (Notice outputs is messing the circle)
Ruby 1.8.x, 93
r=$_.to_f
q=0
e=r-1
(p(('*'*(n=1|2*(r*r-e*e)**0.5)).center r+r)
q+=n+n
e-=2)while-r<e
p q/r/r
Run with $ ruby -p piday
APL: 59
This function accepts a number and returns the two expected items. Works correctly in bonus cases.
{⍪(⊂' *'[1+m]),q÷⍨2×+/,m←(2|v)⌿(q←⍵*2)>v∘.+v←2*⍨⍵-⍳1+2×⍵-1}
Dialect is Dyalog APL, with default index origin. Skill level is clueless newbie, so if any APL guru wants to bring it down to 10 characters, be my guest!
You can try it online on Try APL, just paste it in and put a number after it:
{⍪(⊂' *'[1+m]),q÷⍨2×+/,m←(2|v)⌿(q←⍵*2)>v∘.+v←2*⍨⍵-⍳1+2×⍵-1} 13
*************
*******************
*********************
***********************
*************************
*************************
*************************
*************************
***********************
*********************
*******************
*************
2.98225
And a bash entry: 181 186 190 chars
for((y=-(r=$1,r/2*2);y<=r;y+=2));do for((x=-r;x<=r;++x));do((x*x+y*y<r*r))&&{((++n));echo -n '*';}||echo -n " ";((x<r))||echo;done;done;((s=1000,p=n*2*s/r/r,a=p/s,b=p%s));echo $a.$b
Run with e.g. bash py.sh 13
Python: 148 characters.
Failed (i.e. not short enough) attempt to abuse the rules and hardcode the test cases, as I mentioned in reply to the original post. Abusing it with a more verbose language may have been easier:
a=3.0,3.125,3.16
b="1","23","3677","47899"
r=input()
for i in b[r/3]+b[r/3][::-1]:q=1+2*int(i);print ' '*(int(b[r/3][-1])-int(i))+'*'*q
print a[r/5]
bc: 165, 127, 126 chars
Based on the Python version.
r=read()
for(i=-1;r*2>i+=2;scale=6){n=sqrt(2*i*r-i*i)
scale=0
n=1+n/1*2
j=r-n/2
t+=2*n
while(j--)" "
while(n--)"*"
"
"}
t/r/r
(New line after the last line cannot be omitted here.)
JavaScript (SpiderMonkey) - 118 chars
This version accepts input from stdin and passes the bonus test cases
r=readline()
for(t=0,i=-r;i<r;i++)if(i%2){for(s='',j=-r;j<r;j++){t+=q=i*i+j*j<r*r
s+=q?'*':' '}print(s)}print(t*2/r/r)
Usage: cat 10 | js thisfile.js -- jsbin preview adds an alias for print/readline so you can view in browser
Javascript: 213 163
Updated
r=10;m=Math;a=Array;t=0;l=document;for(i=-r;i<r;i+=2){w=m.floor(m.sqrt(r*r-i*i)*2);t+=w*2;l.writeln(a(m.round(r-w/2)).join(' ')+a(w).join('*'));}l.writeln(t/(r*r))
Nobody said it had to render correctly in the browser - just the output. As such I've removed the pre tags and optimised it further. To view the output you need to view generated source or set your stylesheet accordingly. Pi is less accurate this way, but it's now to spec.
r=10;m=Math;a=Array;t=0;s='';for(i=-r;i<r;i++){w=m.floor((m.sqrt(m.pow(r,2)-m.pow(i,2)))*2);t+=w;if(i%2){z=a(m.round(r-w/2)).join(' ')+a(w).join('*');s+=z+'\n';}}document.write('<pre>'+(s+(t/m.pow(r,2)))+'</pre>')
Unminified:
r=10;
m=Math;
a=Array;
t=0;
s='';
for(i=-r;i<r;i++){
w=m.floor((m.sqrt(m.pow(r,2)-m.pow(i,2)))*2);
t+=w;
if(i%2){
z=a(m.round(r-w/2)).join(' ')+a(w).join('*');
s+=z+'\n';
}
}
document.write('<pre>'+(s+(t/m.pow(r,2)))+'</pre>');
Java: 234
class C{public static void main(String[] a){int x,y,s=0,r=Integer.parseInt(a[0]);for(y=1-r;y<r;y+=2){for(x=1-r;x<r;++x){boolean b=x*x+y*y<=r*r;s+=b?1:0;System.out.print(b?'*':' ');}System.out.println();}System.out.println(s*2d/r/r);}}
Unminified:
class C{
public static void main(String[] a){
int x,y,s=0,r=Integer.parseInt(a[0]);
for(y=1-r;y<r;y+=2){
for(x=1-r;x<r;++x) {
boolean b=x*x+y*y<=r*r;
s+=b?1:0;
System.out.print(b?'*':' ');
}
System.out.println();
}
System.out.println(s*2d/r/r);
}
}
GAWK: 136, 132, 126, 125 chars
Based on the Python version.
{r=$1
for(i=-1;r*2>i+=2;print""){n=1+int((2*i*r-i*i)**.5)*2
t+=2*n/r/r
printf"%*s",r-n/2,""
while(n--)printf"%c","*"}print t}
Locked. This question and its answers are locked because the question is off-topic but has historical significance. It is not currently accepting new answers or interactions.
This is inspired by/taken from this thread: http://www.allegro.cc/forums/thread/603383
The Problem
Assume the user gives you a numeric input ranging from 1 to 7. Input should be taken from the console, arguments are less desirable.
When the input is 1, print the following:
***********
*********
*******
*****
***
*
Values greater than one should generate multiples of the pattern, ending with the one above, but stacked symmetrically. For example, 3 should print the following:
*********** *********** ***********
********* ********* *********
******* ******* *******
***** ***** *****
*** *** ***
* * *
*********** ***********
********* *********
******* *******
***** *****
*** ***
* *
***********
*********
*******
*****
***
*
Bonus points if you print the reverse as well.
*********** ***********
********* *********
******* *******
***** *****
*** ***
* *
***********
*********
*******
*****
***
*
*
***
*****
*******
*********
***********
* *
*** ***
***** *****
******* *******
********* *********
*********** ***********
Can we try and keep it to one answer per language, that we all improve on?
Assembler, 165 bytes assembled
Build Instructions
Download A86 from here
Add a reference to the A86 executable into your DOS search path
Paste the code below into a text file (example: triforce.asm)
Invoke the assembler: a86 triforce.asm
This will create a .COM file called triforce.com
Type triforce to run
This was developed using the standard WinXP DOS box (Start->Programs->Accessories->Command Prompt). It should work with other DOS emulators.
Assemble using A86 and requires WinXP DOS box to run the .COM file it produces. Press 'q' to exit, keys 1-7 to draw the output.
l20:mov ah,7
int 21h
cmp al,'q'
je ret
sub al,'0'
cmp al,1
jb l20
cmp al,7
ja l20
mov [l0-1],al
mov byte ptr [l7+2],6
jmp $+2
mov ah,2
mov ch,0
mov bh,3
l0:mov bl,1
l1:mov dh,0
l3:cmp dh,ch
je l2
mov dl,32
int 21h
inc dh
jmp l3
ret
l2:mov dh,bh
l6:mov cl,12
l5:mov dl,42
cmp cl,bl
ja l4
mov dl,32
cmp dh,1
je l21
l4:int 21h
dec cl
jnz l5
l21:dec dh
jnz l6
mov dl,10
int 21h
mov dl,13
int 21h
l10:inc ch
l9:add bl,2
l7:cmp ch,6
jne l1
l13:add byte ptr [l7+2],6
l11:dec bh
l12:cmp bh,0
jne l0
xor byte ptr [l0+1],10
xor byte ptr [l9+1],40
xor byte ptr [l10+1],8
xor byte ptr [l13+1],40
sub byte ptr [l7+2],12
mov dh,[l0-1]
inc dh
xor [l12+2],dh
xor byte ptr [l11+1],8
xor byte ptr [l1+1],1
inc bh
cmp byte ptr [l0+1],11
je l0
jmp l20
It uses lots of self-modifying code to do the triforce and its mirror, it even modifies the self-modifying code.
GolfScript - 43 chars
~:!6*,{:^' '
*'*'12*' '
^6%.+)*+
-12>!^
6/-*
n}
/
~:!6*,{:^' '*'*'12*' '^6%.+)*+-12>!^6/-*n}/
48 Chars for the bonus
~:!6*,.-1%+{
:^' '*'*'12
*' '^6%.+
)*+-12>
!^6/-
*n}
/
~:!6*,.-1%+{:^' '*'*'12*' '^6%.+)*+-12>!^6/-*n}/
Python - 77 Chars
n=input()
for k in range(6*n):print' '*k+('*'*12+' '*(k%6*2+1))[-12:]*(n-k/6)
n=input()
for k in range(6*n):j=1+k%6*2;print' '*k+('*'*(12-j)+' '*j)*(n-k/6)
89 Chars for the bonus
n=input();R=range(6*n)
for k in R+R[::-1]:print' '*k+('*'*11+' '*11)[k%6*2:][:12]*(n-k/6)
114 Chars Version just using string replacements
u,v=' *';s=(v*11+u)*input()
while s.strip():print s;s=u+s.replace(*((v*2+u,u*3),(v*1+u*10,v*11))[' * 'in s])[:-2]
Unk Chars all in one statement, should work w/ 2.x and 3.x. The enumerate() is to allow the single input() to work for both places you need to use it.
print ('\n'.join('\n'.join(((' '*(6*n))+' '.join(('%s%s%s'%(' '*(5-x),'*'*(2*x+1),' '*(5-x)) for m in range(i + 1)))) for x in range(5,-1,-1)) for n, i in enumerate(range(int(input())-1,-1,-1))))
Yet Another Method
def f(n): print '\n'.join(' '*6*(n-r)+(' '*(5-l)+'*'*(l*2+1)+' '*(5-l)+' ')*r for r in xrange(1, n+1) for l in xrange(6))
f(input())
Ruby - 74 Chars
(6*n=gets.to_i).times{|k|puts' '*k+('*'*(11-(j=k%6*2))+' '*(j+1))*(n-k/6)}
COBOL - 385 Chars
$ cobc -free -x triforce.cob && echo 7| ./triforce
PROGRAM-ID.P.DATA DIVISION.WORKING-STORAGE SECTION.
1 N PIC 9.
1 M PIC 99.
1 value '0100***********'.
2 I PIC 99.
2 K PIC 99.
2 V PIC X(22).
2 W PIC X(99).
PROCEDURE DIVISION.ACCEPT N
COMPUTE M=N*6
PERFORM M TIMES
DISPLAY W(1:K)NO ADVANCING
PERFORM N TIMES
DISPLAY V(I:12)NO ADVANCING
END-PERFORM
DISPLAY ''
ADD 2 TO I
IF I = 13 MOVE 1 TO I ADD -1 TO N END-IF
ADD 1 TO K
END-PERFORM.
K could be returned to outside the group level. An initial value of zero for a numeric with no VALUE clause is compiler-implementation dependent, as is an initial value of space for an alpha-numeric field (W has been cured of this, at no extra character cost). Moving K back would save two characters. -free is compiler-dependant as well, so I'm probably being over-picky.
sed, 117 chars
s/$/76543210/
s/(.).*\1//
s/./*********** /gp
:
s/\*(\**)\*/ \1 /gp
t
:c
s/\* {11}\*/ ************/
tc
s/\* / /p
t
Usage: $ echo 7 | sed -rf this.sed
First attempt; improvements could probably be made...
Ruby 1.9 - 84 characters :
v=gets.to_i
v.times{|x|6.times{|i|puts' '*6*x+(' '*i+'*'*(11-2*i)+' '*i+' ')*(v-x)}}
Perl - 72 chars
die map$"x$_.("*"x(12-($l=1+$_%6*2)).$"x$l)x($n-int$_/6).$/,0..6*($n=<>)
78 chars
map{$l=$_%6*2;print$"x$_,("*"x(11-$l).$"x$l.$")x($n-int$_/6),$/}0..6*($n=<>)-1
87 chars
$n=<>;map{$i=int$_/6;$l=$_%6*2;print$"x$_,("*"x(11-$l).$"x$l.$")x($n-$i),$/}(0..6*$n-1)
97 chars
$n=<>;map{$i=int$_/6;$l=$_%6;print$"x(6*$i),($"x$l."*"x(11-2*$l).$"x$l.$")x($n-$i),$/}(0..6*$n-1)
108 chars
$n=<>;map{$i=int$_/6;$l=$_%6;print ""." "x(6*$i),(" "x$l."*"x(11-2*$l)." "x$l." ")x($n-$i),"\n";}(0..6*$n-1)
Powershell, 78 characters
0..(6*($n=read-host)-1)|%{" "*$_+("*"*(12-($k=1+$_%6*2))+" "*$k)*(.4+$n-$_/6)}
Bonus, 92 characters
$a=0..(6*($n=read-host)-1)|%{" "*$_+("*"*(12-($k=1+$_%6*2))+" "*$k)*(.4+$n-$_/6)}
$a
$a|sort
The output is stored in an array of strings, $a, and the reverse is created by sorting the array. We could, of course, just reverse the array, but it would be more characters to type :)
Haskell - 131 138 142 143 Chars
(⊗)=replicate
z o=[concat$(6*n+m)⊗' ':(o-n)⊗((11-m-m)⊗'*'++(1+m+m)⊗' ')|n<-[0..o-1],m<-[0..5]]
main=getLine>>=mapM_ putStrLn.z.read
This one is longer (146 148 chars) at present, but an interesting, alternate line of attack:
(⊗)=replicate
a↑b|a>b=' ';_↑_='*'
z o=[map(k↑)$concat$(6*n)⊗' ':(o-n)⊗"abcdefedcba "|n<-[0..o-1],k<-"abcdef"]
main=getLine>>=mapM_ putStrLn.z.read
FORTRAN - 97 Chars
Got rid of the #define and saved 8 bytes thanks to implict loops!
$ f95 triforce.f95 -o triforce && echo 7 | ./triforce
READ*,N
DO K=0,N*6
M=2*MOD(K,6)
PRINT*,(' ',I=1,K),(('*',I=M,10),(' ',I=0,M),J=K/6+1,N)
ENDDO
END
125 bytes for the bonus
READ*,N
DO L=1,N*12
K=L+5
If(L>N*6)K=N*12-L+6
M=2*MOD(K,6)
PRINT"(99A)",(32,I=7,K),((42,I=M,10),(32,I=0,M),J=K/6,N)
ENDDO
END
FORTRAN - 108 Chars
#define R REPEAT
READ*,N
DO I=0,6*N
J=MOD(I,6)*2
PRINT*,R(' ',I)//R(R('*',11-J)//R(' ',J+1),N-I/6)
ENDDO
END
JavaScript 1.8 - SpiderMonkey - 118 chars
N=readline()
function f(n,c)n>0?(c||' ')+f(n-1,c):''
for(i=0;i<N*6;i++)print(f(i)+f(N-i/6,f(11-(z=i%6*2),'*')+f(z+1)))
w/ bonus - 151 chars
N=readline()
function f(n,c)n>0?(c||' ')+f(n-1,c):''
function l(i)print(f(i)+f(N-i/6,f(11-(z=i%6*2),'*')+f(z+1)))
for(i=0;i<N*6;i++)l(i)
for(;i--;)l(i)
Usage: js thisfile.js
JavaScript - In Browser - 154 characters
N=prompt()
function f(n,c){return n>0?(c||' ')+f(n-1,c):''}
s='<pre>'
for(i=0;i<N*6;i++)s+=f(i)+f(N-i/6,f(11-(z=i%6*2),'*')+f(z+1))+'\n'
document.write(s)
The non-obfuscated version (before optimizations by gnarf):
var N = prompt();
var S = ' ';
function fill(c, n) {
for (ret=''; n--;)
ret += c;
return ret;
}
var str = '<pre>';
for (i=0; i<N*6; i++) {
str += fill(S, i);
for (j=0; j<N-i/6; j++)
str += fill('*', 11-i%6*2) + fill(S, i%6*2+1);
str += '\n';
}
document.write(str);
Here's a different algorithm that uses replace() to go from one line to the next of each line of a triangle row:
161 characters
N=readline()
function f(n,c){return n>0?(c||' ')+f(n-1,c):''}l=0
for(i=N;i>0;){r=f(i--,f(11,'*')+' ');for(j=6;j--;){print(f(l++)+r)
r=r.replace(/\*\* /g,' ')}}
F#, 184 181 167 151 147 143 142 133 chars
let N,r=int(stdin.ReadLine()),String.replicate
for l in[0..N*6-1]do printfn"%s%s"(r l" ")(r(N-l/6)((r(11-l%6*2)"*")+(r(l%6*2+1)" ")))
Bonus, 215 212 198 166 162 158 157 148 chars
let N,r=int(stdin.ReadLine()),String.replicate
for l in[0..N*6-1]#[N*6-1..-1..0]do printfn"%s%s"(r l" ")(r(N-l/6)((r(11-l%6*2)"*")+(r(l%6*2+1)" ")))
C - 120 Chars
main(w,i,x,y){w=getchar()%8*12;for(i=0;i<w*w/2;)y=i/w,x=i++%w,putchar(x>w-2?10:x<y|w-x-1<y|(x-y)%12>=11-2*(y%6)?32:42);}
Note that this solution prints some trailing spaces (which is okay, right?). It also relies on relational operators having higher precedence than bitwise OR, saving two characters.
124 Chars
main(n,i,k){n=getchar()&7;for(k=0;k<6*n;k++,putchar(10))for(i=-k-1;++i<12*n-2*k-1;putchar(32+10*(i>=0&&(11-i%12>2*k%12))));}
C - 177 183 Chars
#define P(I,C)for(m=0;m<I;m++)putchar(C)
main(t,c,r,o,m){scanf("%d",&t);for(c=t;c>0;c--)for(r=6;r>0;r--){P((t-c)*6+6-r,32);for(o=0;o<c;o++){P(r*2-1,42);P(13-r*2,32);}puts("");}}
C - 222 243 Chars (With Bonus Points)
#define P(I,C)for(m=0;m<I;m++)putchar(C)
main(t,c,r,o,m){scanf("%d",&t);for(c=t-1;-c<2+t;c-=1+!c)for(r=c<0?1:6;c<0?r<7:r>0;r+=c<0?1:-1){P((t-abs(c+1))*6+6-r,32);for(o=0;o<abs(c+1);o++){P(r*2-1,42);P(13-r*2,32);}puts("");}}
This is my first Code Golf submission as well!
Written in C
Bonus points (492 chars):
p(char *t, int c, int s){int i=0;for(;i<s;i++)printf(" ");for(i=0;i<c;i++)printf("%s",t);printf("\n");}main(int a, char **v){int i=0;int k;int c=atoi(v[1]);for(;i<c;i++){p("*********** ",c-i,i);p(" ********* ",c-i,i);p(" ******* ",c-i,i);p(" ***** ",c-i,i);p(" *** ",c-i,i);p(" * ",c-i,i);}for(i=0;i<c;i++){k=c-i-1;p(" * ",1+i,k);p(" *** ",1+i,k);p(" ***** ",1+i,k);p(" ******* ",1+i,k);p(" ********* ",1+i,k);p("*********** ",i+1,k);}}
Without bonus points (322 chars):
p(char *t, int c, int s){int i=0;for(;i<s;i++)printf(" ");for(i=0;i<c;i++)printf("%s",t);printf("\n");}main(int a, char **v){int i=0;int k;int c=atoi(v[1]);for(;i<c;i++){p("*********** ",c-i,i);p(" ********* ",c-i,i);p(" ******* ",c-i,i);p(" ***** ",c-i,i);p(" *** ",c-i,i);p(" * ",c-i,i);}}
First time posting, too!
Lua, 121 chars
R,N,S=string.rep,io.read'*n',' 'for i=0,N-1 do for j=0,5 do X=R(S,j)print(R(S,6*i)..R(X..R('*',11-2*j)..X..S,N-i))end end
123
R,N,S=string.rep,io.read'*n',' 'for i=0,N-1 do for j=0,5 do print(R(S,6*i)..R(R(S,j)..R('*',11-2*j)..R(S,j)..S,N-i))end end
PHP, 153
<?php $i=fgets(STDIN);function r($n,$c=' '){return$n>0?$c.r($n-1,$c):'';}for($l=0;$l<$i*6;){$z=$l%6*2;echo r($l).r($i-$l++/6,r(11-$z,'*').r($z+1))."\n";}
with Bonus, 210
<?php $i=fgets(STDIN);function r($n,$c=' '){return$n>0?$c.r($n-1,$c):'';}$o=array();for($l=0;$l<$i*6;){$z=$l%6*2;$o[]=r($l).r($i-$l++/6,r(11-$z,'*').r($z+1));}print join("\n",array_merge($o,array_reverse($o)));
dc 105 chars
123 129 132 139 141
[rdPr1-d0<P]sP?sn
0sk[1lk6%2*+sj32lkd0<Plnlk6/-si
[[*]12lj-d0<P32ljd0<Pli1-dsi0<I]dsIx
10Plk1+dskln6*>K]dsKx
Mathematica, 46 characters
The answer prints sideways.
TableForm#{Table["*",{l,#},{l},{j,6},{2j-1}]}&
HyperTalk - 272 chars
function triforce n
put"******" into a
put n*6 into h
repeat with y=0 to h-1
put" " after s
put char 1 to y of s after t
repeat n-y div 6
get y mod 6*2
put char 1 to 11-it of (a&a)&&char 1 to it of s after t
end repeat
put return after t
end repeat
return t
end triforce
Indentation is neither needed nor counted (HyperCard automatically adds it).
Miscellanea:
Since there is no notion of console or way to access console arguments in HyperCard 2.2 (that I know of), a function is given instead. It can be invoked with:
on mouseUp
ask "Triforce: "
put triforce(it) into card field 1
end mouseUp
To use this, a card field would be created and set to a fixed-width font. Using HyperCard's answer command would display a dialog with the text, but it doesn't work because:
The answer dialog font (Chicago) is not fixed-width.
The answer command refuses to display long text (even triforce(2) is too long).
Common Lisp, 150 characters:
(defun f(n o)(unless(= n 0)(dotimes(x 6)(format t"~v#{~a~:*~}~-1:*~v#{~?~2:*~}~%"
o" "n"~11#: "(list(- 11(* 2 x))#\*)))(f(1- n)(+ 6 o))))
77 char alternative python solution based on gnibbler's:
n=input()
k=0
exec"print' '*k+('*'*12+' '*(k%6*2+1))[-12:]*(n-k/6);k+=1;"*6*n
Amazingly the bonus came out exactly the same also (101 chars, oh well)
n=input()
l=1
k=0
s="print' '*k+('*'*12+' '*(k%6*2+1))[-12:]*(n-k/6);k+=l;"*6*n
exec s+'l=-1;k-=1;'+s