C语言实例：实现简易日历

//
// @author: 冲哥
// @date: 2021/6/27 20:00
// @description:C语言实现简易日历
// 搜索公众号C语言中文社区后台回复“C语言”，免费领取200G编程资源。

#include <stdio.h>

int main() {
    int year;
    int month;
    int day = 0;
    int day1 = 0;
    printf("请输入年份：");
    scanf("%d", &year);
    printf("请输入月份：");
    scanf("%d", &month);
    printf("一\t二\t三\t四\t五\t六\t日\n");
    //判断年份是否为闰年或这平年
    for (int i = 1900; i < year; i++) {
        if ((i % 4 == 0 && i % 100 != 0) || i % 400 == 0) {
            day = day + 366;
        } else {
            day = day + 365;
        }
    }
    //判断月份
    for (int m = 1; m <= month; m++) {
        switch (m) {
            case 4:
            case 6:
            case 9:
            case 11:
                day1 = 30;
                break;
            case 2:
                if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) {
                    day1 = 29;
                } else {
                    day1 = 28;
                }
                break;
            default:
                day1 = 31;
                break;
        }
        if (m < month) {
            day = day + day1;
        }
    }
    int t;
    t = day % 7;
    //判断这个月的第一天是星期几
    for (int i = 0; i < t; i++) {
        printf("\t");
    }

    for (int i = 1; i <= day1; i++) {
        printf("%d\t", i);
        if ((i + day) % 7 == 0) {
            printf("\n");
        }
    }
    printf("\n\n");
    return 0;
}