#include <stdio.h> int main() { int y,m,d,date=0; int mon[12]={31,28,31,30,31,30,31,31,30,31,30,31}; scanf("%d %d %d",&y,&m,&d); if((y>=10000)||(y<1000)||(m>12)||(m<0)||(d>31)||(d<0))printf("error!"); //判断平闰年 if((y%400==0)||((y%4==0)&&...