C Programming language

# Defining a Function

Following is the source code for a function called add(). This function takes two parameters a and b and returns the addition of them:

/* Simple value addition program*/
int add( int a, int b) 
{
	int c;/* local variable declaration */
	c = a + b;
	return c;
}

* Return type is int, Function name is add and Parameters are a, b is also called Argument for a function.

# Function Declarations

Actual body of the function can be defined separately as show above. The function declaration tells the compiler about function name and how to call the function.

return_type function_name( parameter list );

For the above defined function add(), following is the function declaration:

int add( int a, int b);

/* Parameter names are not important in function declaration 
only their type is required, so following is also valid declaration: */

int add( int, int);

# Calling a Function

To call a function, you simply need to pass the required parameters along with function name, and if function returns a value, then you can store returned value.

#include <stdio.h>
#include <conio.h>
/* function declaration */
int addition( int, int); 
main()
{
	
	int i=1; /* local variable definition */
	i = add(1, 1);
	clrscr();
 }

/* Simple value addition program*/
int add( int a, int b) 
{
	int c; /* local variable declaration */
	c = a + b;
	return c;
}

Functions that return multiple values using Array