C Function Arguments

Functions

C Function Arguments

While calling a function, the arguments can be passed to a function in two ways, Call by value and call by reference.

Type	Description
Call by Value	The actual parameter is passed to a function. New memory area created for the passed parameters, can be used only within the function. The actual parameters can not be modified here.
Call by Reference	Instead of copying variable, address is passed to function as parameters. Address operator(&) is used in the parameter of the called function. Changes in function reflects change of the original variables.

Call by Value

Example:

#include<stdio.h>

/* function declaration */
int addition(int num1, int num2);

int main()
{
    /* local variable definition */
    int answer;
    int num1 = 10;
    int num2 = 5;
    
    /* calling a function to get addition value */
    answer = addition(num1,num2);

    printf("The addition of two numbers is: %d\n",answer);
    return 0;
}

/* function returning the addition of two numbers */
int addition(int a,int b)
{
    return a + b;
}

Program Output:

The addition of two numbers is: 15

Call by Reference

Example:

#include<stdio.h>

/* function declaration */
int addition(int *num1, int *num2);

int main()
{
    /* local variable definition */
    int answer;
    int num1 = 10;
    int num2 = 5;
    
    /* calling a function to get addition value */
    answer = addition(&num1,&num2);

    printf("The addition of two numbers is: %d\n",answer);
    return 0;
}

/* function returning the addition of two numbers */
int addition(int *a,int *b)
{
    return *a + *b;
}

Program Output:

The addition of two numbers is: 15