#include <iostream> using namespace std; int month[] = {0, 31, 28, 31, 30, 31, 30,31, 31, 30, 31, 30, 31}; int get_mday(int year, int mon) { if(mon == 2 && ((year % 4 == 0 && year % 100) || year % 400 == 0)) return month[mon] + 1; else return month[mon]; } int main() { int year...