#include <stdio.h> void NextDay(int &year,int &month,int &day){ int dayofMonth[]={0,31,28,31,30,31,30,31,31,30,31,30,31}; int isLeap=(year%400==0)||(year%4==0&&year%100!=0); if(isLeap){ dayofMonth[2]=29; } else{ dayofMonth[2]=28; } day++; if(day>dayofMonth[month]){ day=1...