Question

我需要编写符合这些准则的程序：

编写一个程序DayOfWeek.java，它将日期作为输入并打印日期所在的星期几。您的程序应该采用三个命令行参数：m（月），d（日）和y（年）。 1月份使用1次，2月份使用2次，依此类推。输出打印0表示星期日，1表示星期一，2表示星期二，依此类推。对于公历，使用以下公式（其中/表示整数除法）：

y0 = y − (14 − m) / 12
x = y0 + y0/4 − y0/100 + y0/400
m0 = m + 12 × ((14 − m) / 12) − 2
d0 = (d + x + 31m0 / 12) mod 7

到目前为止，这是我写的

import java.util.Scanner;

 public class DayOfWeek {
   public static void main(String[] args) {

     Scanner scanner = new Scanner(System.in);

     boolean keepGoing = true;

     while(keepGoing) {
       System.out.println("Month");
       int m = scanner.nextInt();
         if (m < 1 || m > 12) {
           System.out.println("Months are between 1 and 12");
           continue;
         }

       System.out.println("Day");
       int d = scanner.nextInt();
         if (d < 1 || d > 31) {
            System.out.println("Days are between 1 and 31");
            continue;
         }

       System.out.println("Year");
       int y = scanner.nextInt();
         if (y < -10000 || y > 10000) {
            System.out.println("Years are between -10000 and 10000");
            continue;
         }

        int y0 = y - (14 - m) / 12;
        int x = y0 + y0/4 - y0/100 +y0/400;
        int m0 = m + 12 * ((14 - m) / 12) - 2;
        int d0 = (d + x + 31 * m0 / 12) % 7;  
        boolean c = 0 <= d0 <= 6;

          if (c) {
            String b = "Sunday";
          } else {
            if (c) {
              String b = "Monday";
            } else {
              if (c) {
                String b = "Tuesday";
            } else {
              if (c) {
                String b = "Wednesday";
              } else {
                if (c) {
                  String b = "Thursday";
                } else {
                  if (c) {
                    String b = "Friday";
                  } else {
                    if (c) {
                      String b = "Saturday";
                    }                 
                   }
                  }
               }
             }
             }
          } 

        System.out.println("The day of the week is " + b);
    }



  }

 }

当我尝试运行时，它会说

DayOfWeek.java:36: error: bad operand types for binary operator '<='
boolean c = 0 <= d0 <= 6;
                          ^
first type:  boolean
second type: int

DayOfWeek.java:66: error: cannot find symbol
System.out.println("The day of the week is " + b);
                                                      ^
symbol:   variable b
location: class DayOfWeek
2 errors

我真的不知道如何解决这个问题，有人可以帮助我。我对编码还很陌生。

Answer 1

第boolean c = 0 <= d0 <= 6;行应为boolean c = 0 <= d0 && d0 <= 6;

查看java specs以了解如何使用关系运算符。

基本上1＆lt; 0是boolean类型，你不能使用小于和大于布尔值。

编程代码，用于预测给定特定日期时的星期几

1 个答案: