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.

TypeDescription
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 cannot be modified here.
Call by Reference
  • Instead of copying variable; an address is passed to function as parameters.
  • Address operator(&) is used in the parameter of the called function.
  • Changes in function reflect the change of the original variables.
Table of Contents
1. Call by Value
2. Call by Reference

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

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