在while循环中使用switch语句时Java程序没有任何输出？

Question

所以我需要 while 循环中的语句重复，直到用户输入 4（退出程序），但是当我尝试运行程序时，没有任何内容输出到屏幕上（但它编译得很好）。为什么会这样做？这个答案可能很简单，但任何帮助都将不胜感激！

public class Driver 
{
public static void main(String[] args) 
{
    Scanner keyboard = new Scanner(System.in);
    int answer;
    boolean bool = true;

    while(bool);
    {
        System.out.println("\n\tGeometry Calculator\n" + 
                            "\t1. Calculate the Area of a Circle\n" +
                            "\t2. Calculate the Area of a Rectangle\n" +
                            "\t3. Calculate the Area of a Triangle\n" +
                            "\t4. Quit\n");
        System.out.print("\tEnter your choice (1-4): ");
        answer = keyboard.nextInt();

        switch(answer)
        {
            case 1:
                System.out.println("\n\tCalculating the area of a circle...");
                break;
            case 2:
                System.out.println("\n\tCalculating the area of a rectangle...");
                break;
            case 3:
                System.out.println("\n\tCalculating the area of a triangle...");
                break;
            case 4:
                System.out.println("\n\tQuiting...");
                System.exit(0);
                break;
            default:
                System.out.println("\n\tPlease enter a number between 1 and 4.");
        }

        if(answer == 4)
            bool = false;
    }
}

Answer 1

你犯了一个小错误。您在 while 循环之后添加了 ;。只需删除它。你的代码应该是

while(bool)