[Java]建構子(Constructor)與多載(Overload)

package sample2.com;
// Constructor與Class同名
// Constructor不需要任何回傳值
public class Car {
		private int num;
		private double gas;

	public Car(){// 沒有參數的建構子
		num  = 0;
		gas = 0.0;
		System.out.println("生產了汽車");
	}

	public Car(int n,double g){// 兩個參數的建構子
		num  = n;
		gas = g;
		System.out.println("生產了汽車" + num + "，汽油量"+ gas + "的汽車" );
	}

	public void show(){
		System.out.println("車號是" + num );
		System.out.println("汽油量是" + gas);
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Car car1 = new Car();// 建立物件時會自動呼叫沒有參數的建構子
		car1.show();

		Car car2 = new Car(5678,20.5);// 建立物件時呼叫兩個參數的建構子
		car2.show();
	}
}