方法难度大

Question

我的代码似乎部分工作：我的意思是，当我没有进入闰年例如99结束然后我选择2月2日打印29天，我想打印28我有2个separete方法，一个检查年份是否跳跃，另一个打印日期，所以如果有人知道如何修复程序以提高效率，并且没有闰年显示28天，我将不胜感激。谢谢。

这是我的代码：

import java.util.Scanner;
public class LeapYearCheck
{
    public static void main(String[] args) 
    {
        LeapYearCheck.isLeapYear();
        LeapYearCheck.daysInMonth();
    }

    static void isLeapYear()
    {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a year: ");
        int year = input.nextInt();

        if(year % 4 == 0 || year % 400 ==0) 
        {
            System.out.println(year + " is leap year:");
        }
        else 
        {
            System.out.println(year + " is not leap year:");
        }
    }

    static void daysInMonth()
    {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a month :");
        int month = input.nextInt();

        if (month == 2)
        {
            System.out.println("There are 29 days in February: ");
        }
        else if(month == 1)
        {
            System.out.println("The are 31 days in January ");
        }
        else if(month == 2)
        {
            System.out.println("The are 28 days in February ");
        }
        else if(month == 3)
        {
            System.out.println("The are 31 days in March ");
        }
        else if(month == 4)
        {
            System.out.println("The are 30 days in April");
        }
        else if(month == 5)
        {
            System.out.println("The are 31 days in May ");
        }
        else if(month == 6)
        {
            System.out.println("The are 30 days in June  ");
        }
        else if(month == 7)
        {
            System.out.println("The are 31 days in July  ");
        }
        else if(month == 8)
        {
            System.out.println("The are 31 days in August ");
        }
        else if(month == 9)
        {
            System.out.println("The are 30 days in September  ");
        }
        else if(month == 10)
        {
            System.out.println("The are 31 days in  October ");
        }
        else if(month == 11)
        {
            System.out.println("The are 30 days in November ");
        }
        else if(month == 12)
        {
            System.out.println("The are 31 days in December ");
        }
        else 
        {
            System.out.println("Invalid Month, Please enter a number between 1 & 12 Merci: ");
        }
    }
}

Answer 1

您的闰年检查错误。你应该使用

if((year%100 != 0 && year%4 == 0) || year % 400 ==0)) 

Answer 2

它将始终打印

  

二月有29天：

因为第一次检查如下：

if (month == 2)
            {
            System.out.println("There are 29 days in February: ");
            }

另外，检查闰年的正确方法：

if ((year % 400 == 0) || (year % 100 != 0 && year % 4 == 0)) {
   //Leap year.

}

正确的代码：

if (month == 2) {
    if (LeapYearCheck.isLeapYear()) {
        System.out.println("There are 29 days in this month.");
    } else {
        System.out.println("There are 28 days in this month.");
    }
}

让isLeapYear()函数返回boolean（而不是void）。

Answer 3

除了hovanessyan的suggestion之外，考虑到有关年份是否为闰年的信息会在isLeapYear函数的范围内保留和丢失。例如，此函数应返回一个布尔值，并在daysInMonth内调用，因此daysInMonth可以相应地返回28或29。使用Map也可以帮助简化巨大的if-else块。

Answer 4

简单地说：daysInMonth()方法需要知道它是哪一年，然后如果月份数是2，则需要检查它是否是闰年。修改您的方法以接受年份和/或月份作为参数而不是提示它们，然后在main()中提示年份和月份，并将必要的数据传递给每个方法。

Answer 5

首先，如果月号为2，则输入29天。

if (month == 2)
        {
        System.out.println("There are 29 days in February: ");
        }

Answer 6

尝试此代码....

 import java.util.Scanner;
 public class LeapYearCheck {
 static boolean isleep;
 public static void main(String[] args) {
     LeapYearCheck.isLeapYear(); LeapYearCheck.daysInMonth(); 
     } 
 static void isLeapYear() {
     Scanner input = new Scanner(System.in);
     System.out.println("Enter a year: "); 
     int year = input.nextInt();

        if(year % 4 == 0 || year % 400 ==0) 
        {
            isleep=true;
        System.out.println(year + " is leap year:");
        }
        else 
        {
            isleep=false;
            System.out.println(year + " is not leap year:");
        }
    }
        static void daysInMonth()
        {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a month :");
        int month = input.nextInt();
        if (month == 2)
        {
            if(isleep)
             System.out.println("There are 29 days in February: ");
            else 
                System.out.println("There are 28 days in February: ");
        }
        else    if(month == 1)
        {
            System.out.println("The are 31 days in January ");
        }

        else if(month == 3)
        {
            System.out.println("The are 31 days in March ");
        }
        else if(month == 4)
        {
            System.out.println("The are 30 days in April");
        }
        else if(month == 5)
        {
            System.out.println("The are 31 days in May ");
        }
        else if(month == 6)
        {
            System.out.println("The are 30 days in June  ");
        }
        else if(month == 7)
        {
            System.out.println("The are 31 days in July  ");
        }
        else if(month == 8)
        {
            System.out.println("The are 31 days in August ");
        }
        else if(month == 9)
        {
            System.out.println("The are 30 days in September  ");
        }
        else if(month == 10)
        {
            System.out.println("The are 31 days in  October ");
        }
        else if(month == 11)
        {
            System.out.println("The are 30 days in November ");
        }
        else if(month == 12)
        {
            System.out.println("The are 31 days in December ");
        }
        else 
        {
            System.out.println("Invalid Month, Please enter a number between 1 & 12 Merci: ");
        }
        }

}

Answer 7

import java.util.Scanner;
public class LeapYearCheck
{
   public static boolean leap=false;
public static void main(String[] args) 
{
    LeapYearCheck.leap=LeapYearCheck.isLeapYear();
    LeapYearCheck.daysInMonth();
}
    static boolean isLeapYear()
    {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a year: ");
        int year = input.nextInt();

        if(year % 4 == 0 || year % 400 ==0) 
        {
        System.out.println(year + " is leap year:");
        return true;
        }
        else 
        {
            System.out.println(year + " is not leap year:");return false;
        }return false;
    }
        static void daysInMonth()
        {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a month :");
        int month = input.nextInt();
           if(month == 1)
        {
            System.out.println("The are 31 days in January ");
        }
        else if(month == 2)
        {if(leap==true){
            System.out.println("The are 29 days in February ");}
         else{System.out.println("The are 28 days in February ");}} 
        }
        else if(month == 3)
        {
            System.out.println("The are 31 days in March ");
        }
        else if(month == 4)
        {
            System.out.println("The are 30 days in April");
        }
        else if(month == 5)
        {
            System.out.println("The are 31 days in May ");
        }
        else if(month == 6)
        {
            System.out.println("The are 30 days in June  ");
        }
        else if(month == 7)
        {
            System.out.println("The are 31 days in July  ");
        }
        else if(month == 8)
        {
            System.out.println("The are 31 days in August ");
        }
        else if(month == 9)
        {
            System.out.println("The are 30 days in September  ");
        }
        else if(month == 10)
        {
            System.out.println("The are 31 days in  October ");
        }
        else if(month == 11)
        {
            System.out.println("The are 30 days in November ");
        }
        else if(month == 12)
        {
            System.out.println("The are 31 days in December ");
        }
        else 
        {
            System.out.println("Invalid Month, Please enter a number between 1 & 12 Merci: ");
        }
        }

}

你可以检查一下。我没有编译它

Answer 8

您需要知道计算天数的年份和月份：

public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    System.out.println("Enter a year: ");
    int year = input.nextInt();
    if (LeapYearCheck.isLeapYear(year)) {
        System.out.println(year + " is leap year:");
    } else {
        System.out.println(year + " is not leap year:");
    }
    System.out.println("Enter a month :");
    int month = input.nextInt();
    System.out.println("There are " + daysInMonth(year, month) + " in month");
}

static boolean isLeapYear(int year) {
    return (year % 4 == 0) && !(year % 100 == 0) || (year % 400 == 0);
}

static int daysInMonth(int year, int month) {
    if (month == 1) {
        return 31;
    } else if (month == 2) {
        if (isLeapYear(year)) {
            return 29;
        } else {
            return 28;
        }
    } else if (month == 3) {
        return 31;
    } else if (month == 4) {
        return 30;
    } else if (month == 5) {
        return 31;
    } else if (month == 6) {
        return 30;
    } else if (month == 7) {
        return 31;
    } else if (month == 8) {
        return 31;
    } else if (month == 9) {
        return 30;
    } else if (month == 10) {
        return 31;
    } else if (month == 11) {
        return 30;
    } else if (month == 12) {
        return 31;
    } else {
        throw new IllegalArgumentException(
                "Invalid Month, Please enter a number between 1 & 12 Merci: ");
    }
}

Answer 9

使用java.util.Calendar类，你会一直很好。