[Java] 클래스 예제

단순한 클래스 사용 예제 입니다

class J0516_1 {

long number;

String owner;

int point;

int balance;

void use(int amount){

balance += amount;

System.out.println("현재 카드 사용액 : " + balance);

}

void payBill(int amount){

balance -= amount;

System.out.println("지불액: "+amount+", 지불 잔액:"+balance);

addPoint(amount);

}

void addPoint(int amount){

point += amount/1000;

System.out.println("보너스 포인트:" +point);

}

public static void main(String[] args){

J0516_1 j = new J0516_1();

j.number = 3456_7654_8765_5647L;

j.owner = "홍길동";

System.out.print("카드번호 :"+j.number);

System.out.println(",카드소유자 :"+j.owner);

j.use(30000);

j.payBill(10000);

}

}

위 예제에서 get. set 메소드를 추가한 예제입니다.

class J0516_2 {

private long number;

String owner;

private int point;

private int balance;

public long getNumber() {

return number;

}

public void setNumber(long number) {

if(number < 1000_0000_0000_0000L){

System.err.println("잘못된 카드 번호 입니다.");

return;

}

this.number = number;

}

public int getPoint() {

return point;

}

public void setPoint(int point) {

this.point = point;

}

public int getBalance() {

return balance;

}

public void setBalance(int balance) {

this.balance = balance;

}

void use(int amount){

balance += amount;

System.out.println("현재 카드 사용액 : " + balance);

}

void payBill(int amount){

balance -= amount;

System.out.println("지불액: "+amount+", 지불 잔액:"+balance);

addPoint(amount);

}

void addPoint(int amount){

point += amount/1000;

System.out.println("보너스 포인트:" +point);

}

public static void main(String[] args){

J0516_2 j = new J0516_2();

j.number = 3456_7654_8765_5647L;

j.owner = "";

System.out.print("카드번호 :"+j.number);

System.out.println(",카드소유자 :"+j.owner);

j.use(30000);

j.payBill(10000);

}

}

첫번쨰 예제에서 생성자를 추가한 예제입니다.

class J0516_3 {

private long number;

String owner;

private int point;

private int balance;

public J0516_3(String owner){

this.owner = owner;

}

public J0516_3(long number){

this.number = number;

}

public J0516_3(String owner, long number){

this.owner = owner;

this.number = number;

}

public long getNumber() {

return number;

}

public void setNumber(long number) {

if(number < 1000_0000_0000_0000L){

System.err.println("잘못된 카드 번호 입니다.");

return;

}

this.number = number;

}

public int getPoint() {

return point;

}

public void setPoint(int point) {

this.point = point;

}

public int getBalance() {

return balance;

}

public void setBalance(int balance) {

this.balance = balance;

}

void use(int amount){

balance += amount;

System.out.println("현재 카드 사용액 : " + balance);

}

void payBill(int amount){

balance -= amount;

System.out.println("지불액: "+amount+", 지불 잔액:"+balance);

addPoint(amount);

}

void addPoint(int amount){

point += amount/1000;

System.out.println("보너스 포인트:" +point);

}

public static void main(String[] args){

J0516_3 j1 = new J0516_3("권해동");

J0516_3 j2 = new J0516_3(3452_4156_3542_1651L);

j2.owner = "전우치";

J0516_3 j3 = new J0516_3("홍길동", 1651_1651_1232_8641L);

System.out.println("j1: "+ j1.owner + "  " + j1.getNumber());

System.out.println("j2: "+ j2.owner + "  " + j2.getNumber());

System.out.println("j3: "+ j3.owner + "  " + j3.getNumber());

}

}