JAVA - 0516

1번 - 별찍기

package sevenClass;

import java.util.Scanner;

public class Test0516_01 {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		System.out.print("단을 입력>>");
		int n = scan.nextInt();
		for(int i = 1; i <= n; i++) {
			for(int j = n; j > i; j--) {
				System.out.print(" ");
			}
			for(int k = 1; k <= (i*2-1); k++) {
				System.out.print("*");
			}
			System.out.println();
		}
	}
}

 

 

 

결과

단을 입력>>10
         *
        ***
       *****
      *******
     *********
    ***********
   *************
  ***************
 *****************
*******************

 

 

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2번 - 오버 라이딩

package sevenClass;

public class Test0516_02 {
	public static void main(String[] args) {
//		Truck t = new Truck();
//		t.speedUp();
//		t.speedDown();
//		t.name = "프론티어";
//		//업캐스팅
//		//부모클래스 = 자식클래스
//		//다운캐스팅
//		//업캐스팅한 객체를 다시 원래의 형태로 돌릴때
//		Car c = new Truck(); //업캐스팅
//		c.speedUp();
//		Truck t1 = (Truck)c; //다운캐스팅
//		t1.speedUp();
		Car c1, c2;
		Bus b1, b2;
		Truck t1, t2;
		c1 = new Car();
		b1 = new Bus();
		t1 = new Truck();
		System.out.println("[" + c1.print() + "]");
		System.out.println("[" + b1.print() + "]");
		System.out.println("[" + t1.print() + "]");
		//업캐스팅
		c2 = b1;
		//다운캐스팅
		b2 = (Bus)c2;
		System.out.println("[" + b2.print() + "]");
		//업캐스팅
		c2 = t1;
		//다운캐스팅
		t2 = (Truck)c2;
		System.out.println("[" + t2.print() + "]");
		
	}
}

class Car{
	String name = "차";
	String print() {
		return "차의 종류는 " + this.name;
	}
	int velocity;
	void speedUp(){
		velocity += 50;
		System.out.println("속도 " + velocity + "증가");
	}
	void speedDown() {
		velocity -= 50;
		System.out.println("속도 " + velocity + "감소");
	}
}
class Truck extends Car{
	String name = "트럭";
	String print() {
		return "나는 " + this.name;
	}
	int t = 5;
	void speedUp() {
		velocity += 10;
		System.out.println("속도 " + velocity + "증가");
	}
	void speedDown() {
		velocity -= 10;
		System.out.println("속도 " + velocity + "감소");
	}
}

class Bus extends Car{
	String name = "버스";
	String print() {
		return "차의 종류는 "+this.name;
	}
}

 

 

결과

[차의 종류는 차]
[차의 종류는 버스]
[나는 트럭]
[차의 종류는 버스]
[나는 트럭]

 

 

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3번 - 업캐스팅

package sevenClass;

public class Test0516_03 {
	public static void main(String[] args) {
		Ship ship1, ship2;
		MyShip myship1, myship2;
		YourShip yourship1, yourship2;
		//업캐스팅
		ship1 = new Ship();
		myship1 = new MyShip();
		yourship1 = new YourShip();
		//업캐스팅
		ship2 = myship1;
		//다운캐스팅
		myship2 = (MyShip)ship2;
		//업캐스팅
		ship2 = myship1;
		//다운캐스팅
		myship2 = (MyShip)ship2;
	}
}

class Ship{
	String name() {return "배이름";}
}

class MyShip extends Ship{
	String name() {return "타이타닉호";}
}

class YourShip extends Ship{
	String name() {return "해적선";}
}

 

 

 

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2024.05.09 - [자바] - JAVA - 0509

JAVA - 0509