1  public class TV {
  2    int channel = 1; // Default channel is 1
  3    int volumeLevel = 1; // Default volume level is 1
  4    boolean on = false; // By default TV is off
  5    
  6    public TV() {
  7    }
  8    
  9    public void turnOn() {
 10      on = true;
 11    }
 12    
 13    public void turnOff() {
 14      on = false;
 15    }
 16    
 17    public void setChannel(int newChannel) {
 18      if (on && newChannel >= 1 && newChannel <= 120)
 19        channel = newChannel;
 20    }
 21    
 22    public void setVolume(int newVolumeLevel) {
 23      if (on && newVolumeLevel >= 1 && newVolumeLevel <= 7)
 24        volumeLevel = newVolumeLevel;
 25    }
 26    
 27    public void channelUp() {
 28      if (on && channel < 120)
 29        channel++;
 30    }
 31    
 32    public void channelDown() {
 33      if (on && channel > 1)
 34        channel--;
 35    }
 36    
 37    public void volumeUp() {
 38      if (on && volumeLevel < 7)
 39        volumeLevel++;
 40    }
 41    
 42    public void volumeDown() {
 43      if (on && volumeLevel > 1)
 44        volumeLevel--;
 45    }
 46  }