第十一周 项目5 求一年中第几天

#include <iostream>
using namespace std;
int days(int y,int m,int d);
int main()
{
int year,month,day;
cout<<"输入年 月 日"<<endl;
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 n;
if(y%400==0)
switch(m-1)
{
case 0:n=d;break;
case 1:n=31+d;break;
case 2:n=29+31+d;break;
case 3:n=31+29+31+d;break;
case 4:n=31+29+31+30;break;
case 5:n=31+29+31+30+31+d;break;
case 6:n=31+29+31+30+31+30+d;break;
case 7:n=31+29+31+30+31+30+31+d;break;
case 8:n=31+29+31+30+31+30+31+31+d;break;
case 9:n=31+29+31+30+31+30+31+31+30+d;break;
case 10:n=31+29+31+30+31+30+31+31+30+31+d;break;
case 11:n=31+29+31+30+31+30+31+31+30+31+30+d;break;
}
else
switch(m-1)
{
case 0:n=d; break;
case 1: n=31+d;break;
case 2: n=28+31+d;break;
case 3: n=31+28+31+d;break;
case 4:n=31+28+31+30+d;break;
case 5:n=31+28+31+30+31+d;break;
case 6:n=31+28+31+30+31+30+d;break;
case 7:n=31+28+31+30+31+30+31+d;break;
case 8:n=31+28+31+30+31+30+31+31+d;break;
case 9:n=31+28+31+30+31+30+31+31+30+d;break;
case 10:n=31+28+31+30+31+30+31+31+30+31+d;break;
case 11:n=31+28+31+30+31+30+31+31+30+31+30+d;break;
}
return(n);
}

<img src="http://img.blog.csdn.net/20141108212117953?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvaHVhbmd5b25nMDAw/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />