what is header function plz i need it in a very short time

Hello

Functions can be divided into two parts:

1- Function header
2- Function body

eg;

int addition(int a , int b)**
return (a+b);
}

the statement : int addition(int a , int b) is the header of our function ..it should includes the return type which is int in our case , function name , and parameters (a,b in our case)...whatever between **} is our function body.

You can check :
مسائل C++ المثبت بالقسم
for more explanation and examples