题解 | 求四位数各个数位之和

#include <stdio.h>

#include <stdio.h>
int sum(int a)
{
	if (a < 10)
		return a;

	int sum = 0; 
	int tmp = 0;
	while (a)
	{
		/*tmp = a % 10; 
		sum += tmp; */
		sum += (a % 10);
		a /= 10;
	}
	return sum;
}

int main()
{
	int a = 0;
	scanf("%d", &a); 
	int ret = sum(a);
	printf("%d\n", ret);
	return 0;
}