用循环的方法求该年的第几天(2)这种方法很简单，但是有点难想

#include <iostream>  using namespace std;  int main()  {int year,n;       cout<<"请输入任意一个年份year：";        cin>>year;         if (year%400==0)        {              n=29;             cout<<n<< endl; }         else if (year%4==0&&year%100!=0)            {  n=29;               }             else             {  n=28;             }  int month,m,x=0;cin>>month;   for(int i=1;i<month;++i)   {   switch(i)   {case 1:   m=31;break;   case 2:   m=n;break;   case 3:   m=31;break;   case 4:   m=30;break;   case 5:   m=31;break;   case 6:   m=30;break;   case 7:   m=31;break;   case 8:      m=31;break;   case 9:   m=30;break;   case 10:   m=31;break;   case 11:   m=30;break;   case 12:   m=31;break;}   x=x+m;}   int day,sum;   cin>>day;   sum=x+day;   cout<<"为该年的第"<<sum<<"天"<<endl;   return 0;   }