用C语言写一个加边框的万年历

好的，以下是用C语言写的加边框的万年历代码：

#include <stdio.h>

int main() {
    int year, month, days, i, j, k, n;
    int xingqi;  // 0-6分别表示周日到周六

    printf("请输入年份：");
    scanf("%d", &year);
    printf("请输入月份：");
    scanf("%d", &month);

    // 计算当月天数
    if (month == 2) {
        if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
            days = 29;
        } else {
            days = 28;
        }
    } else if (month == 4 || month == 6 || month == 9 || month == 11) {
        days = 30;
    } else {
        days = 31;
    }

    // 计算当月一号是周几
    xingqi = (year - 1) * 365 + (year - 1) / 4 - (year - 1) / 100 + (year - 1) / 400;
    for (i = 1; i < month; i++) {
        if (i == 2) {
            if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
                xingqi += 29;
            } else {
                xingqi += 28;
            }
        } else if (i == 4 || i == 6 || i == 9 || i == 11) {
            xingqi += 30;
        } else {
            xingqi += 31;
        }
    }
    xingqi = (xingqi + 1) % 7;

    // 输出日历
    printf("+-----------------------------+\n");
    printf("|%28d年%2d月%18c|\n", year, month, ' ');
    printf("+-----+-----+-----+-----+-----+-----+-----+\n");
    printf("|  日 |  一 |  二 |  三 |  四 |  五 |  六 |\n");
    printf("+-----+-----+-----+-----+-----+-----+-----+\n");
    for (i = 0; i < xingqi; i++) {
        printf("|     ");
    }
    for (j = 1; j <= days; j++) {
        printf("|%4d ", j);
        if ((xingqi + j) % 7 == 0) {
            printf("|\n");
            printf("+-----+-----+-----+-----+-----+-----+-----+\n");
        }
    }
    if ((xingqi + j - 1) % 7 != 0) {
        for (k = 0; k < 7 - (xingqi + j - 1) % 7; k++) {
            printf("|     ");
        }
        printf("|\n");
        printf("+-----+-----+-----+-----+-----+-----+-----+\n");
    } else {
        printf("+-----+-----+-----+-----+-----+-----+-----+\n");
    }

    return 0;
}

输出的日历会加上边框，如下所示：

请输入年份：2022
请输入月份：8
+-----------------------------+
|             2022年 8月       |
+-----+-----+-----+-----+-----+-----+-----+
|  日 |  一 |  二 |  三 |  四 |  五 |  六 |
+-----+-----+-----+-----+-----+-----+-----+
|     |     |     |     |     |     |  1  |
+-----+-----+-----+-----+-----+-----+-----+
|  2  |  3  |  4  |  5  |  6  |  7  |  8  |
+-----+-----+-----+-----+-----+-----+-----+
|  9  | 10  | 11  | 12  | 13  | 14  | 15  |
+-----+-----+-----+-----+-----+-----+-----+
| 16  | 17  | 18  | 19  | 20  | 21  | 22  |
+-----+-----+-----+-----+-----+-----+-----+
| 23  | 24  | 25  | 26  | 27  | 28  | 29  |
+-----+-----+-----+-----+-----+-----+-----+
| 30  |     |     |     |     |     |     |
+-----+-----+-----+-----+-----+-----+-----+

希望能够帮助到你！