cartest2.java

来自「java2 primer plus一书源程序」· Java 代码 · 共 81 行

public class CarTest2 {

    public static void turnOn( Car c ) {
      c.isRunning = true;
    }

    public static void turnOff( Car c ) {
      c.isRunning = false;
    }

    public static void accelerate( Car c ) {
      switch( c.engineType ) {
      case Car.V4: 
        speedUp( c, 2 );
        break;
      case Car.V6: 
        speedUp( c, 3 );
        break;
      case Car.V8: 
        speedUp( c, 4 );
        break;
      case Car.V10: 
        speedUp( c, 5 );
        break;
      }
    }

    public static void speedUp( Car c, int amount ) {
      if( c.isRunning == false ) {
        // Do nothing - car is not running!
        return;
      }

      if( ( c.currentSpeed + amount ) >= c.topSpeed ) {
        c.currentSpeed = c.topSpeed;
      }
      else {
        c.currentSpeed += amount;
      }
    }

    public static void decelerate( Car c ) {
      if( c.isRunning == false ) { 
        // Do nothing - car is not running!
        return;
      }

      if( ( c.currentSpeed - 5 ) <= 0 ) {
        c.currentSpeed = 0;
      }
      else {
        c.currentSpeed -= 5;
      }
    }

  public static void main( String[] args ) {
    // Define the attributes of the car
    Car c1 = new Car();
    c1.engineType = Car.V10;
    c1.bodyType = Car.CONVERTIBLE; 
    c1.topSpeed = 185;
    c1.isRunning = false;
    c1.currentSpeed = 0;

    // Do some things with the car
    turnOn( c1 );
    for( int i=0; i<10; i++ ) { 
      accelerate( c1 );
      System.out.println( "Current Speed: " + c1.currentSpeed );
    }    

    for( int i=0; i<5; i++ ) { 
      decelerate( c1 );
      System.out.println( "Current Speed: " + c1.currentSpeed );
    }
    turnOff( c1 );
  }

}