# C Program to reverse a given number using Recursive function

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"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
Updated on 15-Mar-2021 10:21:05