palindrome and armstrong numbers

#include <stdio.h>

int main()
{
    printf("***menu*** \n");
    printf("***choose 1 for palindrome number*** \n");
    printf("***choose 2 for armstrong number*** \n");
    int ch;
    printf("enter your choice: ");
    scanf("%d",&ch);
    if(ch==1)
    {
        int reverse=0;
        int num,a,r;
        printf("enter any number:");
        scanf("%d",&num);
        a=num;
        while(a>0)
        {
            r=a%10;
            reverse=reverse*10+r;
            a=a/10;
        }
        if (reverse==num)
        {
            printf("it is a palindrome number");
        }
        else
        {
            printf("it is not a palindrome number");
        }
    }
    else if(ch==2)
    {
        int sum=0;
        int num,a,r;
        printf("enter the 3 digit number:");
        scanf("%d",&num);
        a=num;
        while(a>0)
        {
            r=a%10;
            sum=sum+(r*r*r);
            a=a/10;
        }
        if (sum==num)
        {
            printf("it is a armstrong number");
        }
        else
        {
            printf("it is not a armstrong number");
        }
    }
    else
    {
        printf("invalid choice");
    }

    return 0;
}