JAVA电视遥控器类与测试

下面是一个简单的JAVA电视遥控器类和测试代码：

public class TVRemote {
    private int channel;
    private int volume;
    private boolean isOn;

    public TVRemote() {
        channel = 1;
        volume = 50;
        isOn = false;
    }

    public void turnOn() {
        isOn = true;
        System.out.println("TV is turned on.");
    }

    public void turnOff() {
        isOn = false;
        System.out.println("TV is turned off.");
    }

    public void setChannel(int channel) {
        if (isOn) {
            this.channel = channel;
            System.out.println("Channel is set to " + channel);
        } else {
            System.out.println("TV is turned off. Cannot set channel.");
        }
    }

    public void setVolume(int volume) {
        if (isOn) {
            this.volume = volume;
            System.out.println("Volume is set to " + volume);
        } else {
            System.out.println("TV is turned off. Cannot set volume.");
        }
    }

    public void printStatus() {
        System.out.println("TV is " + (isOn ? "on" : "off"));
        if (isOn) {
            System.out.println("Channel is " + channel);
            System.out.println("Volume is " + volume);
        }
    }
}

测试代码：

public class TVRemoteTest {
    public static void main(String[] args) {
        TVRemote tv = new TVRemote();

        tv.printStatus();   // TV is off

        tv.turnOn();        // TV is turned on
        tv.setChannel(3);   // Channel is set to 3
        tv.setVolume(70);   // Volume is set to 70
        tv.printStatus();   // TV is on, Channel is 3, Volume is 70

        tv.turnOff();       // TV is turned off
        tv.setChannel(5);   // TV is turned off. Cannot set channel.
        tv.setVolume(80);   // TV is turned off. Cannot set volume.
        tv.printStatus();   // TV is off
    }
}

输出结果：

TV is off
TV is turned on
Channel is set to 3
Volume is set to 70
TV is on
Channel is 3
Volume is 70
TV is turned off
TV is turned off. Cannot set channel.
TV is turned off. Cannot set volume.
TV is off

这个简单的电视遥控器类实现了开关、设置频道和音量以及打印电视状态的功能。测试代码展示了如何使用这个类。