2014-09-23-Tue
Overriding |
class AA
{
void callMe() { System.out.println("class AA's callMe"); }
}
class BB extends AA
{
void callMe() { System.out.println("class BB's callMe"); }
}
class CC extends BB
{
void callMe() { System.out.println("class CC's callMe"); }
} class Overriding
{
public static void main(String[] args)
{
AA ref = new AA();
ref.callMe();
ref=new BB(); // AA타입 ref에 BB객체 선언 ~ 다형성 원리로 가능
ref.callMe();
ref = new CC();
ref.callMe();
}
} |
 |
- Overriding(재정의)
- Polymophism(다형성)
* 깨알 톡 *
무진장 피곤 졸림.........그분이 오시려나보다.......
오늘 네트워크 복습은 무싄일이 있더라도 해야한당
고시프 예습도 해야하ㅡㄴㄴ데
개 피곤해~~~~~~~~~~~
동적 바인딩
:: callMe()가 여러개 있는데 연결되는것은 동적으로 이루어진다.
컴파일러 상에서는 알 수 없지만 실행시 결정
정적 바인딩
:: 대부분의 코드는 거진 정적 바인딩 ~ 컴파일 시 결정
|
AA ref = new AA();
ref.callMe();
//ref=new BB(); // AA타입 ref에 BB객체 선언 ~ 다형성 원리로 가능
ref.callMe();
ref = new CC();
ref.callMe(); |
 |
|
class AA
{
int x =1;
void callMe() { System.out.println("class AA's callMe"); }
}
class BB extends AA
{
int x=2;
void callMe() { System.out.println("class BB's callMe"); }
}
class CC extends BB
{
int x=3;
void callMe() { System.out.println("class CC's callMe"); }
} class Overriding
{
public static void main(String[] args)
{
AA ref = new AA();
ref.callMe();
System.out.format("x is %d\n",ref.x);
ref=new BB();
ref.callMe();
System.out.format("x is %d\n",ref.x);
ref = new CC();
ref.callMe();
System.out.format("x is %d\n",ref.x);
}
} |
 |
타입이 맞는 변수형만 사용해야한다.
|
class AA
{
int x =1;
void callMe() { System.out.println("class AA's callMe"); }
}
class BB extends AA
{
int x=2;
void callMe() { System.out.println("class BB's callMe"); }
}
class CC extends BB
{
int x=3;
void callMe() { System.out.println("class CC's callMe"); }
} class Overriding
{
public static void main(String[] args)
{
AA ref = new AA();
ref.callMe();
System.out.format("x is %d\n",ref.x);
ref=new BB();
ref.callMe();
System.out.format("x is %d\n",ref.x);
ref = new CC();
ref.callMe();
System.out.format("x is %d\n",ref.x);
BB refB = new CC();
ref.callMe();
System.out.format("x is %d\n",refB.x);
}
} |
 |
더워~~~~~~!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!하앍 하앍ㅠㅠㅠㅠㅠㅠㅠㅠㅠ
|
class Product
{
int price;
static int totalSale=0;
Product(int pr){price=pr;} }
class Tv extends Product
{
Tv(){super(100);}
public String toString(){return "Tv Purchased:";}
}
class Computer extends Product
{
Computer(){super(200);}
public String toString(){return "Computer Purchased";}
}
class Audio extends Product
{
Audio(){super(150);}
public String toString(){return "Audio Purchased";}
}
class Buyer
{
String name;
int money;
Product [] cart =new Product[10];
int count=0;
Buyer(String name, int money)
{
this.name=name;
this.money=money;
}
//메서드 오버로딩
//-> Tv대신 product 따로 설정
void buy(Product p) { money=money-p.price; cart[count++]=p; Product.totalSale+=p.price;}
//void buy(Tv t){money=money-t.price;}
//void buy(Computer c){money-=c.price;}
//void buy(Audio a){money-=a.price;} void printProduct(){
int sum=0;
for(int i=0;i<count;i++)
{
System.out.println(cart[i]);
sum+=cart[i].price;
}
System.out.println("Sum : "+ sum);
} }
class Pr07Ploy
{
public static void main(String[] args)
{
Tv tv1=new Tv();
Computer comp1=new Computer();
Audio audio1=new Audio();
Buyer b1=new Buyer("Chul-soo",1000);
b1.buy(tv1);
b1.buy(comp1);
//System.out.println(tv1);
System.out.println(b1.name+":Money left="+b1.money );
/*
Product p1 = new Tv();
Product p2 = new Computer();
b1.buy(p1);
b1.buy(p2);
*/
Product[] p = new Product[3];
p[0]=new Tv();
p[1]=new Computer();
for( int i=0;i<2;i++){
b1.buy(p[i]);
}
System.out.println(b1.name+":Money left="+b1.money );
b1.printProduct();
Buyer b2 = new Buyer("YoungHee",200);
b2.buy(tv1);b2.buy(audio1);
b2.printProduct();
System.out.println("Total sale :: "+Product.totalSale );
}
} |
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