Write a C Program to Swap Two Numbers Using Call by Reference

What are Pointers?

A pointer is a variable whose value is the address of another variable, i.e., direct address of the memory location. Like any variable or constant, you must declare a pointer before using it to store any variable address.

The general form of a pointer variable declaration is −

• type *var-name;

Here, type is the pointer’s base type; it must be a valid C data type and var-name is the name of the pointer variable.

The asterisk * used to declare a pointer is the same asterisk used for multiplication. However, in this statement the asterisk is being used to designate a variable as a pointer.

The unary or monadic operator & gives the “address of a variable’”.

The indirection or dereference operator * gives the “contents of an object pointed to by a pointer”.

Below is the source code for C Program to Swap Two Numbers Using Call by Reference which is successfully compiled and run on Windows System to produce desired output as shown below :

SOURCE CODE : :

/*  C Program to Swap Two Numbers Using Call by Reference  */

#include<stdio.h>

void cyclicSwap(int *a,int *b,int *c);

int main()
{
    int a, b, c;

    printf("Enter a :: ");
    scanf("%d",&a);
    printf("\nEnter b :: ");
    scanf("%d",&b);
    printf("\nEnter c :: ");
    scanf("%d",&c);

    printf("\nValues Before swapping :: \n");
    printf("\ta = %d\tb = %d\tc = %d\n",a,b,c);

    cyclicSwap(&a, &b, &c);

    printf("\nValues After swapping :: \n");
    printf("\ta = %d\tb = %d\tc = %d\n",a,b,c);

    return 0;
}
void cyclicSwap(int *a,int *b,int *c)
{

    int temp;

    // swapping in cyclic order
    temp = *b;
    *b = *a;
    *a = *c;
    *c = temp;
}

Output : :

/*  C Program to Swap Two Numbers Using Call by Reference  */

Enter a :: 7

Enter b :: 8

Enter c :: 9

Values Before swapping ::
        a = 7   b = 8   c = 9

Values After swapping ::
        a = 9   b = 7   c = 8

Process returned 0

Above is the source code for C Program to Swap Two Numbers Using Call by Reference which is successfully compiled and run on Windows System.The Output of the program is shown above .