C Program to reverse a given number using Recursive function

"Recursive function" is something which calls itself again in the body of the function.

For example,

• A function fact ( ), which computes the factorial of an integer ‘N’, which is the product of all whole numbers from 1 to N.

• fact ( ) with an argument of 1 (or) 0, the function returns 1. otherwise, it returns n*fact (n-1), this happens until ‘n’ equals 1.

Fact (5) =5* fact (4)    =5*4*3* fact (3)    =5*4*3*2* fact (2)    =5*4*3*2*1 fact (1)    =5*4*3*2*1    = 120.

Example

Following is the C program for use of recursive function to reverse a number −

#include<stdio.h> main ( ){    int n,f;    int fact (int);    clrscr ( );    printf ("enter a number");    scanf ("%d", &n);    f= fact (n);    printf (factorial value = %d",f); } int fact (int n){    int f;    if ( ( n==1) || (n==0))       return 1;    else       f= n*fact (n-1);    return f; }

Output

The output is given below −

Enter a number 5 Factorial value = 120

Given below is another C Program to reverse a given number using Recursive function −

#include<stdio.h> int sum=0,rem; int main(){    int num,revNum;    printf("enter number:
");    scanf("%d",&num);    revNum=revNumFunction(num);//calling function to reverse the given number    printf("the number after reverse :%d",revNum);    return 0; } revNumFunction(int num){    if(num){       rem=num%10;       sum=sum*10+rem;       revNum(num/10);    }    else       return sum; }

Output

The output is as follows −

enter number: 1357 the number after reverse is :7531