C Program to find the sum of individual digitis of a number till the sum becomes a single digit

/* C Program to find the sum of individual digits of a long integer until the sum becomes
a single digit */

#include <stdio.h>
int main()
{
    long number;
    int sum=0;
    int digit;

    printf("Enter the number\n");
    scanf("%ld",&number);

    while(number>0)
    {
        sum=0;
        while(number>0)
        {
            digit=number%10;
            number=number/10;
            sum=sum+digit;
        }
        if(sum>9)
        {
            number=sum;
        }
    }

    printf("The sum is %d",sum);

    return 0;
}

C Program to find the number of digits in a long number

/* C Program to find the number of digits in a given long integer number */

#include <stdio.h>

int main()
{
    long num;
    int count=0;

    printf("Enter the number\n");
    scanf("%ld",&num);

    while(num>0)
    {
        num=num/10;
        count++;
    }

    printf("The number of digits in the give number is %d",count);

    return 0;
}

C Program to find the sum of all digits in a number

/* C Program to find the sum of all digits in a given long number accepted from the user */

#include <stdio.h>
#include <stdlib.h>

int main()
{
    long number;
    int sum=0;
    printf("Enter a long number\n");
    scanf("%ld",&number);

    while(number>0)
    {
        sum=sum+(number%10);
        number=number/10;
    }
    printf("The sum of the digits is %d",sum);
    return 0;
}