题目：输入某年某月某日，判断这一天是这一年的第几天？
代码如下：
#include <stdio.h>/*** 输入某年某月某日，判断这一天是这一年的第几天？* create by hangli*/int main(int argc, char *argv[]){int y, m, d, days, February;printf("请输入年份:");scanf("%d", &y);printf("请输入月份:");scanf("%d", &m);printf("请输入天:");scanf("%d", &d);// 先判断是是否是闰年if (y % 400 == 0 || (y % 4 == 0 && y % 100 != 0))February = 29;elseFebruary = 28;switch (m){// 分别计算每个月的天数case 1:days = 0;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 2:days = 31;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 3:days = 31 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 4:days = 62 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 5:days = 92 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 6:days = 123 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 7:days = 153 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 8:days = 184 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 9:days = 215 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 10:days = 245 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 11:days = 276 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;case 12:days = 306 + February;printf("%d年%d月%d日是一年中的第%d天！", y, m, d, days + d);break;default:printf("你输入月份错误!");break;}system("PAUSE");return 0;}
