写一个简单的计数器，有菜单，可按菜单提示进行操作

Question

问题遇到的现象和发生背景

问题相关代码，请勿粘贴截图

package counter;

import java.util.*;





//public class TestCounter {
//
//}
class Counter{ 
    int value = 0; 
    int number;
    Counter(int number){ 
        this.number = number;
    } 
    public void increment() { 
        value++; 
    } 
    public void decrement() {
        value--; 
    }

    public int getCountValue(){ 
        return value; 
    } 
}
public class TestCounter {
    public static void main(String args[]){
        System.out.println("*********************");
        System.out.println("    1.计数器加一     ");
        System.out.println("    2.计数器减一     ");
        System.out.println("    3.退出           ");
        System.out.println("*********************");
//        int number;
        Scanner reader = new Scanner(System.in);
        Counter number = new Counter(reader.nextInt());
        number.increment();
        while(number >= 1 && number <= 3) {
            if(number == 1) {
                number.increment();
            }
        } 
        Counter c = new Counter(); 
        c.increment(); 
        System.out.println(c.getCountValue()); 
//        c.reset(); 
        System.out.println(c.getCountValue());
        reader.close();
        
    } 
}

运行结果及报错内容

我的解答思路和尝试过的方法

我想要达到的结果

按相应的键，有相应的效果
1.计数器加一
2．计数器减一
3.退出

Answer 1

import java.util.Scanner;

public class TestCounter {
    static class Counter {
        int value = 0;
        int number;
        Counter() {
        }
        Counter(int number) {
            this.number = number;
        }

        public void increment() {
            System.out.print( value +  " + 1 = ");
            value++;
        }

        public void decrement() {
            System.out.print( value +  " - 1 = ");
            value--;
        }

        public int getCountValue() {
            return value;
        }
    }

    public static void main(String args[]) {
        System.out.println("*********************");
        System.out.println("    1.计数器加一     ");
        System.out.println("    2.计数器减一     ");
        System.out.println("    3.退出           ");
        System.out.println("*********************");
        Scanner reader = new Scanner(System.in);
        Counter counter = new Counter();
        //循环监听输入
        while (reader.hasNext()) {
            int n = reader.nextInt();
            switch (n) {
                case 1:
                    counter.increment();
                    break;
                case 2:
                    counter.decrement();
                    break;
                case 3:
                    return;

            }
            System.out.println(counter.getCountValue());
        }
        reader.close();
    }
}

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