#include <iostream> using namespace std; int perday[]={0,31,28,31,30,31,30,31,31,30,31,30,31}; void nextday(int &year,int &month,int &day){ if(year%400==0||(year%100!=0&&year%4==0))perday[2]=29; else perday[2]=28; day++; if(day>perday[month]){ mo...