题解 | #计算日期到天数转换#

#include <iostream>
#include <ctime>
using namespace std;

int main()
{
    int y, m, d;

    while (cin >> y >> m >> d) {
                
        struct tm t1;
        t1.tm_year = y - 1900;
        t1.tm_mon = m -1;
        t1.tm_mday = d;
        
        struct tm t2 = t1;
        t2.tm_year = y - 1 - 1900;
        t2.tm_mon = 11;
        t2.tm_mday = 31;
        
        time_t tt1 = mktime(&t1);
        time_t tt2 = mktime(&t2);
        
        int res = difftime(tt1, tt2) / (60 * 60 * 24);
        
        cout << res << endl;
    }
}