星期几

Question

我想制作一个程序，从用户输入中获取一天，然后告诉他们前一天和后一天。用户还应该能够输入要添加的日期和程序应该在当天输出。

例如用户输入1 =星期一，明天是= 2星期二昨天= 3周日

如果用户其星期一（1），并增加了12天输出应为星期六（6）

的说问题是无论何时“theWeekDay”大于7，它都不会输出，因为TheDay（）;没有超过7的条件。请帮助我！

非常感谢你！

import java.util.Scanner; 
import java.util.Scanner; 

public class Problem_3 { 

    public static void main(String[] args) { 
     Scanner input = new Scanner(System.in); 

     int theWeekDay; 
     System.out.println("What Day Is It?"); 
     theWeekDay = input.nextInt(); 
     Days one = new Days(theWeekDay); 
     System.out.println("Today It Is: "); 
     one.TheDay(theWeekDay); 
     System.out.println("Yesterday It Was: "); 
     one.PreviousDay(theWeekDay); 
     System.out.println("Tomorrow It Is: "); 
     one.NextDay(theWeekDay); 
     System.out.println("How Many Days To Add?"); 
     int x = input.nextInt(); 
     System.out.println("Now It Is: "); 
     one.AddedDays(x); 
    } 
} 

class Days { 
    private int theWeekDay; 

    public Days(int theWeekDay) { 
     this.theWeekDay = theWeekDay; 
    } 

    public int getTheWeekDay() { 
     return theWeekDay; 
    } 

    public void setTheWeekDay(int theWeekDay) { 
     this.theWeekDay = theWeekDay; 
    } 

    public int TheDay(int theWeekDay) { 
     // an arra days of week + then add days in it 
     if (theWeekDay == 0) { 
      theWeekDay = theWeekDay + 7; 
     } 

     if (theWeekDay == 1) { 
      System.out.println("Monday"); 
     } else if (theWeekDay == 2) { 
      System.out.println("Tuesday"); 
     } else if (theWeekDay == 3) { 
      System.out.println("Wednsday"); 
     } else if (theWeekDay == 4) { 
      System.out.println("Thursday"); 
     } else if (theWeekDay == 5) { 
      System.out.println("Friday"); 
     } else if (theWeekDay == 6) { 
      System.out.println("Saturday"); 
     } else if (theWeekDay == 7) { 
      System.out.println("Sunday"); 
     } 
     return theWeekDay; 
    } 

    public int PreviousDay(int theWeekDay) { 
     theWeekDay = theWeekDay - 1; 
     return TheDay(theWeekDay); 
    } 

    public int NextDay(int theWeekDay) { 
     theWeekDay = theWeekDay + 1; 
     if (theWeekDay > 7) { 
      theWeekDay = 1; 
     } 
     return TheDay(theWeekDay); 
    } 

    public int AddedDays(int AddedDays) { 
     getTheWeekDay(); 
     theWeekDay = theWeekDay + AddedDays; 
     return TheDay(theWeekDay); 
    } 
} 

Answer 1

如果你想承担更大的价值那7有效，你绝对应该用模运算。这样的事情：

if(theWeekDay > 7) { 
    theWeekDay = theWeekDay % 7; 
} 

否则，你应该抛出和异常。

Answer 2

您的if else必须涵盖所有情况....

后添加其他

else if(theWeekDay == 7){ 
     System.out.println("Sunday"); 
    } 

类似：

if(theWeekDay == 1){ 
    System.out.println("Monday"); 
}else if(theWeekDay == 2){ 
    System.out.println("Tuesday"); 
}else if(theWeekDay == 3){ 
    System.out.println("Wednsday"); 
}else if(theWeekDay == 4){ 
    System.out.println("Thursday"); 
}else if(theWeekDay == 5){ 
    System.out.println("Friday"); 
}else if(theWeekDay == 6){ 
    System.out.println("Saturday"); 
}else if(theWeekDay == 7){ 
    System.out.println("Sunday"); 
}else{ 
    System.out.println("Invalid input"); 
} 
return theWeekDay; 

Answer 3

正如user629735所说，在您的公式中使用模数。

public int AddedDays(int AddedDays) { 
    getTheWeekDay(); 
    theWeekDay = (theWeekDay + AddedDays) % 7; 
    return TheDay(theWeekDay); 
}