C Program to reverse no. using recursion

Program

#include<stdio.h>
int reverse_function(int);

int main()
{
int num,reverse_number;

//User would input the number
printf("\nEnter any number:");
scanf("%d",&num);

//Calling user defined function to perform reverse
reverse_number=reverse_function(num);
printf("\nAfter reverse the no is :%d",reverse_number);
return 0;
}
int sum=0,rem;
int reverse_function(int num)
{
if(num){
rem=num%10;
sum=sum*10+rem;
reverse_function(num/10);
}
else
return sum;

}