题解 | #添加逗号#

#include <stdio.h>

int count = 0;
void Fun(int n)
{
	if (n > 10)
	{
		count++;
		Fun(n / 10);
	}
	if (count % 3 == 0&&count!=0)
	{
		printf("%d", n % 10);
		printf(",");
		count--;
	}
	else
	{
		printf("%d", n % 10);
		count--;
	}
}
int main()
{
	int n;
	scanf("%d", &n);
	Fun(n);
	return 0;
}