get the whole word string after finding the word in a text - function

Question

i have a problem developing this function, i have this text..
Testing Function
ok
US.Cool
rwgehtrhjyw54 US_Cool
fhknehq is ryhetjuy6u24
gflekhtrhissfhejyw54i
my function :
function TForm5.FindWordInString(sWordToFind, sTheString : String): Integer;
var
i : Integer; x:String;
begin
Result := 0;
for i:= 1 to Length(sTheString) do
begin
x := Copy(sTheString,i,Length(sWordToFind));
if X = sWordToFind then
begin
if X.Length > sWordToFind.Length then
begin
Result := 100;
break;
end else
begin
Result := i;
break;
end;
end;
end;
end;
now, i want X to be US.Cool, but here its always = US, because i want to check the length of sWordToFind and X.

Answer 1

After clarification, this question is about getting length of a word searched by its starting substring within a string. For example when having string like this:
fhknehq is ryhetjuy6u24
When you execute a desired function for the above string with the following substrings, you should get results like:
hknehq → 0 → substring is not at the beginning of a word
fhknehq → 7 → length of the word because substring is at the beginning of a word
yhetjuy6u24 → 0 → substring is not at the beginning of a word
ryhetjuy6u24 → 12 → length of the word because substring is at the beginning of a word
If that is so, I would do this:
function GetFoundWordLength(const Text, Word: string): Integer;
const
Separators: TSysCharSet = [' '];
var
RetPos: PChar;
begin
Result := 0;
{ get the pointer to the char where the Word was found in Text }
RetPos := StrPos(PChar(Text), PChar(Word));
{ if the Word was found in Text, and it was at the beginning of Text, or the preceding
char is a defined word separator, we're at the beginning of the word; so let's count
this word's length by iterating chars till the end of Text or until we reach defined
separator }
if Assigned(RetPos) and ((RetPos = PChar(Text)) or CharInSet((RetPos - 1)^, Separators)) then
while not CharInSet(RetPos^, [#0] + Separators) do
begin
Inc(Result);
Inc(RetPos);
end;
end;

Answer 2

I spend a few times on your idea, so i wrote below codes, but it is not a good way for develop a Start With search. with some research you can find builtin functions, that provide better performance. you can try StrUtils.SearchBuf Function it will provide a full function string search.
anyway this code are working with SPACE separator, I hope it will be useful for you:
function TForm5.FindWordInString(sWordToFind, sTheString : String): Integer;
var
i : Integer; x:String;
flag : Boolean;
begin
Result := 0;
i := 1;
flag := False;
while True do
begin
if i > Length(sTheString) then Break;
if not flag then
x := Copy(sTheString,i,Length(sWordToFind))
else
begin
if sTheString[i] = ' ' then Break;
x := x + sTheString[i];
end;
if (X = sWordToFind) then
begin
flag := True;
if (X.Length >= sWordToFind.Length) and
(sTheString[i + Length(sWordToFind)] = ' ') then
break
else
i := i + Length(sWordToFind) -1;
end;
i := i + 1;
end;
Result := Length(x);
end;