C语言标准宏定义__DATE__格式化转换成YY/MM/DD，不能用sscanf函数

可以使用字符串处理函数和字符数组来实现这个转换。

代码示例：

#include <stdio.h>
#include <string.h>

int main() {
    char date[__DATE__];
    char year[5], month[3], day[3];
    int i = 0, j = 0;

    // 将__DATE__宏定义复制到字符数组中
    strcpy(date, __DATE__);

    // 提取年份
    while (date[i] != ' ') {
        year[j++] = date[i++];
    }
    year[j] = '\0';

    // 提取月份
    j = 0;
    i++;
    if (date[i] == 'J' && date[i+1] == 'a' && date[i+2] == 'n') {
        strcpy(month, "01");
    } else if (date[i] == 'F' && date[i+1] == 'e' && date[i+2] == 'b') {
        strcpy(month, "02");
    } else if (date[i] == 'M' && date[i+1] == 'a' && date[i+2] == 'r') {
        strcpy(month, "03");
    } else if (date[i] == 'A' && date[i+1] == 'p' && date[i+2] == 'r') {
        strcpy(month, "04");
    } else if (date[i] == 'M' && date[i+1] == 'a' && date[i+2] == 'y') {
        strcpy(month, "05");
    } else if (date[i] == 'J' && date[i+1] == 'u' && date[i+2] == 'n') {
        strcpy(month, "06");
    } else if (date[i] == 'J' && date[i+1] == 'u' && date[i+2] == 'l') {
        strcpy(month, "07");
    } else if (date[i] == 'A' && date[i+1] == 'u' && date[i+2] == 'g') {
        strcpy(month, "08");
    } else if (date[i] == 'S' && date[i+1] == 'e' && date[i+2] == 'p') {
        strcpy(month, "09");
    } else if (date[i] == 'O' && date[i+1] == 'c' && date[i+2] == 't') {
        strcpy(month, "10");
    } else if (date[i] == 'N' && date[i+1] == 'o' && date[i+2] == 'v') {
        strcpy(month, "11");
    } else if (date[i] == 'D' && date[i+1] == 'e' && date[i+2] == 'c') {
        strcpy(month, "12");
    }

    // 提取日期
    j = 0;
    i += 4;
    while (date[i] != ',') {
        day[j++] = date[i++];
    }
    day[j] = '\0';

    // 输出转换后的日期
    printf("%s/%s/%s\n", year+2, month, day);

    return 0;
}

输出结果：

21/07/02