用函数完成如何写代码

代码如下：

#include <stdio.h>
int days(int y,int m)
{
    if (m == 1 || m == 3 ||m == 5 ||m == 7 ||m == 8 ||m == 10 ||m == 12)
    {
        return 31;
    }else if (m == 4 ||m == 6 ||m == 9 ||m == 11)
    {
        return 30;
    }else
    {
        if(y%4==0 && y%100!=0 || y%400==0)
            return 29;
        else
            return 28;
    }
}

int main()
{
    int y,m;
    printf("请输入年份:");
    scanf("%d",&y);
    printf("请输入月份:");
    scanf("%d",&m);
    printf("%d年%d月共有%d天\n",y,m,days(y,m));
    return 0;
}