Question

所以我试图在控制台上创建一个Java计算器，它的工作正常，但是当我得到结果时，我希望它像循环一样重启，但我无法弄明白。

import java.util.Scanner;

public class calculator {

    public static void main(String[] args0) {
        Scanner test = new Scanner(System.in);
        int x;
        int y;
        String c;
        try {
            System.out.println("Insert a number ");
            x = test.nextInt();
            System.out.println("insert a value e.g * / + -");
            c = test.next();
            System.out.println("Insert another number");
            y = test.nextInt();

            if (c.equals("*")) {
                System.out.println("the total is " + x * y);
            } else if (c.equals("+")) {
                System.out.println("the total is " + (x + y));
            } else if (c.equals("-")) {
                System.out.println("the total is " + (x - y));
            } else if (c.equals("/")) {
                System.out.println("the total is " + (x / y));
            } else {
                System.out.println("you are an idiot");
            }
        } catch (Exception e) {
            System.out.println("Please enter correct value.");
        }
    }
}

Answer 1

使用while + break。以下是工作版本：

import java.util.Scanner;

public class Calculator {

    public static void main(String[] args0) {
        Scanner test = new Scanner(System.in);

        int x;
        int y;
        String c;

        while (true) {
            try {
                System.out.println("Insert a number ");
                x = test.nextInt();

                System.out.println("insert a value e.g * / + -");
                c = test.next();

                System.out.println("Insert another number");
                y = test.nextInt();

                if (c.equals("*")) {
                    System.out.println("the total is " + x * y);
                } else if (c.equals("+")) {
                    System.out.println("the total is " + (x + y));

                } else if (c.equals("-")) {
                    System.out.println("the total is " + (x - y));
                } else if (c.equals("/")) {
                    System.out.println("the total is " + (x / y));
                } else {
                    System.out.println("you are an idiot");
                }

            } catch (Exception e) {
                System.err.println("Please enter correct value.");
            }

            System.out.println("Do you wish to continue(y/n)?");
            if (test.next().equals("n")) {
                break;
            }
        }

    }
}

Answer 2

您可以使用while循环：

public static void main(String[] args0) {
    Scanner test = new Scanner(System.in);
    while(true) {
    ....

}

如果要停止计算器，则需要输入ctrl - c。

另一种方法，使用布尔值flag并让用户自杀是否继续：

public static void main(String[] args0) {
    boolean flag = true;
    Scanner test = new Scanner(System.in);
    while(flag) {
        ....
        System.out.println("enter y for continue, n for exit");
        c = test.next();
        if (c.equals("n")) {
           flag = false;
        } 
    }
}

Answer 3

在尝试之前插入while循环并将所有内容放在it.put while（true）中，这将无限重复。如果你想按某个键来停止make if条件并将其中断。

DECLARE @str VARCHAR(MAX)=''

DECLARE @where VARCHAR(max)=''''

IF 1>2 
BEGIN
SET @where= 'Test_Group_Id=1'
END
ELSE
BEGIN
SET @where='Party_Master_Id=1'
END

SET @str = 'SELECT * FROM dbo.Party_Details WHERE 1=1 and ' + @where

EXECUTE(@str)

如何在给出答案后重新启动计算器

3 个答案: