display integer as sequence of digits and find sum of its digits

/*P5.4 Program to display integer as sequence of digits and find sum of its digits*/

#include<stdio.h>
void display(long int n);
void Rdisplay(long int n);
int sumdigits( long int n);

main( )
{
    long int num;
    printf("Enter number : ");
    scanf("%ld", &num);
    printf("%d\n",sumdigits(num));
    printf("\n");
    display(num);
    printf("\n");
    Rdisplay(num);
    printf("\n");
}/*End of main()*/

/*Finds the sum of digits of an integer*/
int sumdigits(long int n)
{
    if( n/10 == 0 ) /* if n is a single digit number*/
        return n;
    return n%10 + sumdigits(n/10);       
}/*End of sumdigits()*/

/*Displays the digits of an integer*/
void display(long int n)
{
    if( n/10==0 )
    {
        printf("%d",n);
        return;
    }
    display(n/10);
    printf("%d",n%10);   
}/*End of display()*/

/*Displays the digits of an integer in reverse order*/
void Rdisplay(long int n)
{
    if(n/10==0)
    {
        printf("%d",n);
        return;
    }
    printf("%d",n%10);
    Rdisplay(n/10);
}/*End of Rdisplay()*/