C語言之各個位數上的數值之和

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

void main()
{
    int num;
    int sum = 0;
    int x,y;

    printf("請輸入一個整數：");
    scanf("%d",&num);

    y = num;

    while (y != 0)
    {
        x = y % 10;
        sum += x;
        y = (int)(y / 10);
    }

    printf("各位數字之和為%d\n",sum);

    system("pause");
    return ;
}