第十一周项目5今天是今年的第几天

问题及代码：

/*
*Copyringht (c) 2014,烟台大学计算机学院
*All right reserved.
*文件名称： test.cpp
*作    者：马明城
*完成日期：2014年11月9日
*版本号：  v1.0

*问题描述:
*输入描述：
*程序输出：
*/
#include <iostream>

using namespace std;
int days(int y,int m,int d);
int main()
{ int year,month,day,s;
    cout << "输入年 月 日：" ;
    cin>>year>>month>>day;
    cout<<"这是该年的第"<<days(year,month,day)<<"天"<<endl;
    return 0;
}
int days(int y,int m,int d)
{
    int s;
 if((y%4==0)&&(y%100!=0)||(y%400==0))
 {
     switch(m)
     {
         case 1: s=d; break;
         case 2: s=d+31; break;
         case 3: s=d+31+29; break;
         case 4: s=d+31+29+31; break;
         case 5: s=d+31+29+31+30; break;
         case 6: s=d+31+29+31+30+31; break;
         case 7: s=d+31+29+31+30+31+30; break;
         case 8: s=d +31+29+31+30+31+30+31; break;
         case 9: s=d+31+29+31+30+31+30+31+31; break;
         case 10: s=d+31+29+31+30+31+30+31+31+30; break;
         case 11: s=d+31+29+31+30+31+30+31+31+30+31; break;
         case 12: s=d+31+29+31+30+31+30+31+31+30+31+30; break;
     }
 }
else
    switch(m)
{
    case 1: s=d;
         case 2: s=d+31; break;
         case 3: s=d+31+28; break;
         case 4: s=d+31+28+31; break;
         case 5: s=d+31+28+31+30; break;
         case 6: s=d+31+28+31+30+31; break;
         case 7: s=d+31+28+31+30+31+30; break;
         case 8: s=d +31+28+31+30+31+30+31; break;
         case 9: s=d+31+28+31+30+31+30+31+31; break;
         case 10: s=d+31+28+31+30+31+30+31+31+30; break;
         case 11: s=d+31+28+31+30+31+30+31+31+30+31; break;
         case 12: s=d+31+28+31+30+31+30+31+31+30+31+30; break;
}


return s;

}
/*
*Copyringht (c) 2014,烟台大学计算机学院
*