#include <stdio.h> //第一种简单数组方法 int main() { int year; int month; int day; scanf("%d %d %d", &year, &month, &day); int sum = day; //闰年数组: int leap_year[12] = { 31,29,31,30,31,30,31,31,30,31,30,31 }; // 1 2 3 4 5 6 7 8 9 10 11 12 //平年数组: int common_year[12] = { 31,28,31,30,...