what is a called function and calling function in c - Wikitechy https://www.wikitechy.com/interview-questions/tag/what-is-a-called-function-and-calling-function-in-c/ Interview Questions Thu, 06 Oct 2022 10:21:12 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 https://www.wikitechy.com/interview-questions/wp-content/uploads/2025/10/cropped-wikitechy-icon-32x32.png what is a called function and calling function in c - Wikitechy https://www.wikitechy.com/interview-questions/tag/what-is-a-called-function-and-calling-function-in-c/ 32 32 What are called and calling functions ? https://www.wikitechy.com/interview-questions/c/what-are-called-and-calling-functions/ https://www.wikitechy.com/interview-questions/c/what-are-called-and-calling-functions/#respond Thu, 06 Oct 2022 10:21:12 +0000 https://www.wikitechy.com/interview-questions/?p=4938
  • A function call is very important in programming.
  • When we need to call a function, it is called inside a program.
  • A function which is being called by the parent functions is known as called functions
  • Function which is being called is known as calling function.
  • A function is called by the program whenever it is needed.
  • Functions are called by its name in the main program.
  • We can pass parameters to the functions that are being called in the main function.

    • Syntax

    Add(a, b) // a and b are the parameters

    Calling a function in C program

    Add.c

    #include <stdio.h>  
    int add(int a, int b);   
    void main()  
    {  
      
    int sum;  
    int a, b;  
    printf(" Enter the first and second number \n");  
    scanf("%d %d", &a, &b);  
    sum = add(a, b); // call add() function  
    printf( "The sum of the two number is %d", sum);  
    }  
    int add(int n1, int n2) // pass n1 and n2 parameter  
    {  
    int c;  
    c = n1 + n2;  
    return c;  
    }

    Output

    Call by value

    • When an single or multiple values of an argument are copied into formal parameters of a function, this type of functions is known as Call By Value.
    • It does not change the value of the function`s actual parameter.

    Call by Value in C programming

    Call_Value.c

    #include <stdio.h>  
    int main()  
    {  
    int x = 10, y = 20;  
    printf (" x = %d, y = %d from main before calling the function", x, y);  
    CallValue(x, y);  
    printf( "\n x = %d, y = %d from main after calling the function", x, y);  
    }  
    int CallValue( int x, int y)  
    {  
    x = x + 5;  
    y = y + 5;  
    printf (" \nx = %d, y = %d from modular function", x, y);  
    }

    Output

    Call By Reference

    • As name suggests call by reference is a method, where the address of the actual argument is copied into the function call’s formal parameter.
    • This type of method is known as Call by Reference.
    • If we make some changes in the formal parameters, it shows the effect in the value of the actual parameter.

    Call by Reference in C programming

    Call_Ref.c

    #include <stdio.h>  
    int main()  
    {  
    int x = 10, y = 20;  
    printf (" x = %d, y = %d from main before calling the function", x, y);  
    CallValue (&x, &y);  
    printf( "\n x = %d, y = %d from main after calling the function", x, y);  
    }  
    int CallRef( int *a, int *b)  
    {  
    *a = *a + 5;  
    *b = *b + 5;  
    printf (" \nx = %d, y = %d from modular function", *a, *b);  
    }

    Output

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