In the output first the text " Sum is : " is getting printed and then the function is getting called. Please check this code - output

Question

#include<iostream>
using namespace std;
int sum();
int main() {
cout << "Sum is: " << sum() << endl;
return 0;
}
int sum() {
int num1,num2;
cout << "Enter 2 numbers: " << endl;
cin >> num1 >> num2;
return (num1 + num2);
}
I am not getting a correct out put. First "Sum is: " getting called and then the function in output.
Output is given as:- "Sum is: Enter 2 numbers: " and then enter numbers. But it gives correct output. But its not coming as I want.

Answer 1

Your sum() function gives the "Enter 2 numbers: " output, so when you call that function after your main() gives the output "Sum is: ", it is clear that the complete output is "Sum is: Enter 2 numbers: ".
You need to rewrite your code (especially the function sum()) to get the output in the order you want it to be.
Example:
#include<iostream>
using namespace std;
int sum();
int main() {
sum();
return 0;
}
int sum() {
int num1,num2;
cout << "Enter 2 numbers: " << endl;
cin >> num1 >> num2;
cout << "Your sum is: " << (num1+num2) << endl;
return 0;
}

Answer 2

You're not getting "Enter 2 numbers" first because in the main function this line is called first.
cout << "Sum is: " << sum() << endl;
which is equivalent to
cout << "Sum is:";
cout << sum();
cout << endl;
The first line prints
Sum is:
To the standard output and then it calls the function sum()
which prints Enter 2 numbers:
So the standard output is:
Sum is:
Enter 2 numbers:
Then the function returns and you get the result and the newline.
To change this either take the input in the main function or just take the return value of the function in a variable;
#include<iostream>
using namespace std;
int sum();
int main() {
int s = sum;
cout << "Your sum is: " << s << endl;
return 0;
}
int sum() {
int num1,num2;
cout << "Enter 2 numbers: " << endl;
cin >> num1 >> num2;
return (num1 + num2);
}