Inline Function in C++ Qus - 1

 C++ provides an inline functions to reduce the function call overhead. Inline function is a function that is expanded in line when it is called. When the inline function is called whole code of the inline function gets inserted or substituted at the point of inline function call. This substitution is performed by the C++ compiler at compile time. 

inline return-type function-name(parameters)

{

    // function code

}  

Inlining is only a request to the compiler, not a command. Compiler can ignore the request for inlining. Compiler may not perform inlining in following conditions:

1) If a function contains a loop. (for, while, do-while)

2) If a function contains static variables.

3) If a function is recursive.

4) If a function return type is other than void, and the return statement doesn’t exist in function body.

5) If a function contains switch or goto statement.

Inline function may increase compile time overhead if someone changes the code inside the inline function then all the calling location has to be recompiled because compiler would require to replace all the code once again to reflect the changes, otherwise it will continue with old functionality.

inline int square(int a)

{

  return a*a;

}

int main() {

  clrscr();

cout<<square(5)<<endl;

cout<<square(6)<<endl;

getch();

}