編程代碼，它是當給出一個具體的日期

Question

我需要編寫，根據這些準則落在程序：

寫一個程序DayOfWeek.java接受一個日期作爲輸入並打印那一天的那一天正在落下。你的程序應該有三個命令行參數：m（月），d（日）和y（年）。對於1月份使用1，2月份使用2，等等。對於週日輸出打印0，週一輸出1，週二輸出2，等等。使用下面的公式，對於格里高利曆（其中/表示整數除法）：

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 

到目前爲止，這是我自己寫的

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); 
    } 



    } 

} 

當我嘗試但運行它，它說

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決這個問題，有人可以幫助我。我對編碼還很陌生。

Answer 1

線boolean c = 0 <= d0 <= 6;應boolean c = 0 <= d0 && d0 <= 6;

看看在java specs獲取如何使用關係運算符的想法。

基本上1 < 0是布爾類型的，你不能在布爾值上使用小於和大於。