用c语言改写这段代码def week(m, d): # 判断输入日期是否合法 if m < 1 or m > 12 or d < 1 or d > 31: return -1 if (m == 4 or m == 6 or m == 9 or m == 11) and d > 30: return -1 if m == 2: if (d > 29) or (d == 29 and (year % 4 != 0 or (year % 100 == 0 and year % 400 != 0))): return -1 # 计算该日期是该年的第几天 days_in_month = [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334] day_of_year = days_in_month[m-1] + d if m > 2 and ((year % 4 == 0 and year % 100 != 0) or year % 400 == 0): day_of_year += 1 # 计算该日期是该年的第几周 first_day = (2 - (year % 4)) % 7 + 1 # 确定该年1月1日是星期几 if first_day == 1: first_week_days = 1 else: first_week_days = 8 - first_day week_of_year = (day_of_year - first_week_days)//7 + 1 return week_of_year# 输入一组日期进行测试dates = [(1, 1), (1, 5), (13, 1), (2, 29), (4, 31)]year = 2022 # 假设计算的年份是2022年for m, d in dates: print(f"The week of {m}/{d} in {year} is {week(m, d)}")

好的，以下是用C语言改写的代码：

#include <stdio.h>

int week(int m, int d, int year){
    // 判断输入日期是否合法
    if (m < 1 || m > 12 || d < 1 || d > 31){
        return -1;
    }
    if ((m == 4 || m == 6 || m == 9 || m == 11) && d > 30){
        return -1;
    }
    if (m == 2){
        if ((d > 29) || (d == 29 && (year % 4 != 0 || (year % 100 == 0 && year % 400 != 0)))){
            return -1;
        }
    }
    
    // 计算该日期是该年的第几天
    int days_in_month[12] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
    int day_of_year = days_in_month[m-1] + d;
    if (m > 2 && ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)){
        day_of_year += 1;
    }
    
    // 计算该日期是该年的第几周
    int first_day = (2 - (year % 4)) % 7 + 1;  // 确定该年1月1日是星期几
    int first_week_days;
    if (first_day == 1){
        first_week_days = 1;
    }
    else{
        first_week_days = 8 - first_day;
    }
    int week_of_year = (day_of_year - first_week_days) / 7 + 1;
    return week_of_year;
}

int main(){
    int dates[5][2] = {{1, 1}, {1, 5}, {13, 1}, {2, 29}, {4, 31}};
    int year = 2022;
    for (int i = 0; i < 5; i++){
        int m = dates[i][0];
        int d = dates[i][1];
        printf("The week of %d/%d in %d is %d\n", m, d, year, week(m, d, year));
    }
    return 0;
}

首先，在C语言中，没有Python中的列表和字符串格式化输出，需要使用数组和printf函数来实现。其次，需要注意Python中的整数除法//在C语言中是/，需要进行修改。最后，需要在调用函数时传入年份参数。

运行结果与Python代码一样，不再赘述。