Question

以下是我计算年龄的代码。

我想在执行案例1时再次显示主菜单：Enter your Birth date(DD):。

我正在休息，但那不起作用。

此处我的控制台在完成后再次显示Select your choice.。

我想表明：import java.util.Calendar; import java.util.Scanner; public class Switch { public static void main(String args[]) { System.out.println("Select your choice"); System.out.println("1. To Calculate your Age"); System.out.println("2. Calculator"); System.out.println("3. To Exit"); boolean exit=false; Scanner sc1=new Scanner(System.in); int choice=sc1.nextInt(); do{ switch(choice) { case 1: Calendar c1 = Calendar.getInstance(); int currDate = c1.get(Calendar.DATE); //System.out.println(currDate); int currMonth = c1.get(Calendar.MONTH)+1; //System.out.println(currMonth); int currYear=c1.get(Calendar.YEAR); //System.out.println(currYear); Scanner sc2=new Scanner(System.in); System.out.println("Enter your Birth date(DD): "); int birthDate=sc2.nextInt(); System.out.println("Enter your Birth month(MM): "); int birthMonth=sc2.nextInt(); System.out.println("Enter your Birth year(YYYY): "); int birthYear=sc2.nextInt(); int calculateDate=0; calculateDate=currDate-birthDate; int calculateMonth=currMonth-birthMonth; int calculateYear=currYear-birthYear; System.out.println("You are : "+ calculateDate+"days "+" "+calculateMonth+"months "+calculateYear+"years OLD"); System.out.println("thank you.."); System.out.println("\n"); break; case 2: System.out.println("This is case 2"); break; case 3: exit=true; break; } }while(!exit); } }任何想法？

m_words

Answer 1

将下面的行移到do ...中，而while执行至少一次。

        System.out.println("Select your choice");
        System.out.println("1. To Calculate your Age");
        System.out.println("2. Calculator");
        System.out.println("3. To Exit");
        Scanner sc1 = new Scanner(System.in);
        int choice = sc1.nextInt();

SwitchCase.java

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

public class SwitchCase {
    public static void main(String args[]) {
        boolean exit = false;
        do {
            System.out.println("Select your choice");
            System.out.println("1. To Calculate your Age");
            System.out.println("2. Calculator");
            System.out.println("3. To Exit");
            Scanner sc1 = new Scanner(System.in);
            int choice = sc1.nextInt();
            switch (choice) {
            case 1:
                Calendar c1 = Calendar.getInstance();
                int currDate = c1.get(Calendar.DATE);
                // System.out.println(currDate);
                int currMonth = c1.get(Calendar.MONTH) + 1;
                // System.out.println(currMonth);
                int currYear = c1.get(Calendar.YEAR);
                // System.out.println(currYear);
                Scanner sc2 = new Scanner(System.in);
                System.out.println("Enter your Birth date(DD): ");
                int birthDate = sc2.nextInt();
                System.out.println("Enter your Birth month(MM): ");
                int birthMonth = sc2.nextInt();
                System.out.println("Enter your Birth year(YYYY): ");
                int birthYear = sc2.nextInt();
                int calculateDate = 0;
                calculateDate = currDate - birthDate;
                int calculateMonth = currMonth - birthMonth;
                int calculateYear = currYear - birthYear;
                System.out.println("You are : " + calculateDate + "days " + " "
                        + calculateMonth + "months " + calculateYear
                        + "years OLD");
                System.out.println("thank you..");
                System.out.println("\n");
                break;
            case 2:
                System.out.println("This is case 2");
                break;
            case 3:
                exit = true;
                break;
            }
        } while (!exit);
    }
}

示例运行

Select your choice
1. To Calculate your Age
2. Calculator
3. To Exit
1
Enter your Birth date(DD): 
1
Enter your Birth month(MM): 
1
Enter your Birth year(YYYY): 
1920
You are : 14days  6months 97years OLD
thank you..


Select your choice
1. To Calculate your Age
2. Calculator
3. To Exit

Answer 2

只需分配＆＃34; true＆＃34;执行案例1时变量退出。

Answer 3

您已选择在循环外选择选项。选择选项的代码必须在循环内。

以下是可能有效的更新代码：

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

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

public class Switch {
    public static void main(String args[])
    {
        boolean exit;
        do{
                System.out.println("Select your choice");
                System.out.println("1. To Calculate your Age");
                System.out.println("2. Calculator");
                System.out.println("3. To Exit");
                exit=false;
                Scanner sc1=new Scanner(System.in);
                int choice=sc1.nextInt();
                    switch(choice)
                    {   
                    case 1:

                        Calendar c1 = Calendar.getInstance();
                        int currDate = c1.get(Calendar.DATE);
                        //System.out.println(currDate);

                        int currMonth = c1.get(Calendar.MONTH)+1;
                        //System.out.println(currMonth);

                        int currYear=c1.get(Calendar.YEAR);
                        //System.out.println(currYear);
                        Scanner sc2=new Scanner(System.in);
                        System.out.println("Enter your Birth date(DD): ");
                        int birthDate=sc2.nextInt();

                        System.out.println("Enter your Birth month(MM): ");
                        int birthMonth=sc2.nextInt();

                        System.out.println("Enter your Birth year(YYYY): ");
                        int birthYear=sc2.nextInt();
                        int calculateDate=0;


                        calculateDate=currDate-birthDate;

                        int calculateMonth=currMonth-birthMonth;
                        int calculateYear=currYear-birthYear;

                        System.out.println("You are : "+ calculateDate+"days "+" "+calculateMonth+"months "+calculateYear+"years OLD");
                        System.out.println("thank you..");
                        System.out.println("\n");
                        break;
                case 2:

                       System.out.println("This is case 2");
                       break;

                case 3:

                        exit=true;
                        break;

                }
            }while(!exit);
    }
}

想要返回Switch Case中的主菜单

3 个答案: