朋友们，这个根据年月日输出本年天数的题怎么说

#include <iostream>
using namespace std;
int main()
{
    int year,mon,day;
    char ch;
    int cc = 0,i;
    cin >> year>>ch>>mon>>ch>>day;
    int arr[]={0,31,28,31,30,31,30,31,31,30,31,30,31};
    if( year%4==0 && year%100!=0 || year%400==0)
        arr[2] = 29;
    for (i=1;i<mon;i++)
    {
        cc += arr[i];
    }
    cc += day;
    cout << cc;
    return 0;
}