如何用c语言制作万年历，要求包括闰年判断，星期判断，年历输出，月历输出

用C语言制作万年历，首先需要考虑闰年的判断、星期的计算以及详细的日期输出。这里提供一个基础的示例，使用`stdio.h`和`time.h`库：

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

// 判断是否是闰年
int is_leap_year(int year) {
    if (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)) return 1;
    return 0;
}

// 获取给定日期对应的星期几
char get_weekday(int day, int month, int year) {
    time_t raw_time;
    struct tm * timeinfo;

    time(&raw_time);
    timeinfo = localtime(&raw_time);

    // 调整月份和日子，因为localtime默认从1月1日开始
    timeinfo->tm_mon = month - 1; // 0-based index
    timeinfo->tm_mday = day;

    // 重构日期并获取星期
    mktime(timeinfo);

    return (char)(timeinfo->tm_wday + 1); // Monday is 1, Sunday is 7
}

void print_calendar(int year, int month) {
    printf("%s\n", calendar_names[month - 1]);
    printf("-------------------------\n");
    int days_in_month = is_leap_year(year) ? 29 : (month == 2 && !is_leap_year(year) ? 28 : (month > 2 ? 30 : 31));
    
    for (int i = 1; i <= days_in_month; ++i) {
        printf("%2d ", i);
        
        // 输出星期几
        char weekday = get_weekday(i, month, year);
        switch (weekday) {
            case '1':
                printf("| ");
                break;
            case '2':
                printf("|/");
                break;
            case '3':
                printf("|\\");
                break;
            case '4':
                printf("| ");
                break;
            case '5':
                printf("|-");
                break;
            case '6':
                printf("|_");
                break;
            case '7':
                printf("|+");
                break;
        }

        if ((i % 7) == 0) {
            printf("\n");
        }
    }
    printf("\n");
}

// 常量定义
const char* calendar_names[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};

int main() {
    int year = 2023, month = 1;
    while (true) {
        printf("Year: %d\nMonth: %s\n", year, calendar_names[month - 1]);
        print_calendar(year, month);
        printf("\nDo you want to continue? (y/n): ");
        char input[2];
        fgets(input, sizeof(input), stdin);
        input[0] = toupper(input[0]); // 将输入转换为大写
        if (input[0] != 'Y') break;
        scanf("%d", &month); // 验证用户输入是否合法
        if (month < 1 || month > 12) month = 1; // 设置回月
        year++;
    }
    return 0;
}