Inline Functions

Every time a function is called, it takes a lot of extra time in executing series of instruction such as jumping to function, saving registers, returning to calling functions.And much execution time is spent in such operations to perform.

To eliminate the cost of calls and to increase execution speed, C++ gives new function called inline function.
Inline function is a function that is expanded in a line when it is called.

Syntax:
            inline return_type function_name (Arguments)
             {
              //Function Body
               }

When we prefix the keyword 'inline' , the function becomes an inline function. All inline function must be defined before they are called.

Example:-
#include<iostream.h>
#include<conio.h>
inline float mul(float x, float y)
{
return(x * y);
}
inline double div(double p, double q)
{
return(p/q);
}
void main( )
{
float a = 12.345, b = 9.82;
clrscr( );
cout<<"\n\n\t Result of multiplication is --->"<<mult(a,b);
cout<<"\n\n\t Result of the division is --->"<<div(a,b);
getch( );
}

Output:-
Result of multiplication is --->121.227898
Result of the division is --->1.257128

Inline function will not work where functions contains loops, switch or goto exist.Also it will not work if a function contain static variable or if a inline function is recursive.