로또 번호 구하기(복습)
public class Lotto { public static void main(String[] args) { int[] lottoArr = new int[6]; for (int i = 0; i < 6; i++) { lottoArr[i] = (int) (Math.random() * 45) + 1; for (int j = 0; j < i; j++) { if (lottoArr[j] == lottoArr[i]) { i--; break; } } } for (int i = 0; i < 6; i++) { System.out.println(lottoArr[i]); } } }
class Box {
private String conts;
Box(String cont) {
this.conts = cont;
}
public String toString() {
return conts;
}
}
public class BoxTest {
public static void main(String[] args) {
Box[] ar = new Box[3];
// 배열에 안스턴스 생성
ar[0] = new Box("First");
ar[1] = new Box("Second");
ar[2] = new Box("Third");
//저장된 인스턴스의 참조
System.out.println(ar[0]);
System.out.println(ar[1]);
System.out.println(ar[2]);
}
}
public class StringArray {
public static void main(String[] args) {
String[] sr = new String[3];
sr[0] = new String("Java");
sr[1] = new String("System");
sr[2] = new String("Compier");
int cnum = 0;
for (int i = 0; i < sr.length; i++)
cnum += sr[i].length();
System.out.println("총 문자의 수: " + cnum);
}
}
아래가 돌아가도록 하시오.
main(){ Circle[] circleArr = new Circle[2]; circleArr[0] = new Circle(10); circleArr[1] = new Circle(10); //System.out.println(circleArr[0].getArea()); //System.out.println(circleArr[1].getArea()); double areas = Circle.getArrArea(circleArr); System.out.println(areas); }
class Circle {
// private final double PI = 3.14;
private double rad;
public Circle(int rad) {
this.rad = rad;
}
public double getArea() {
return (rad * rad) * Math.PI;
}
public static double getArrArea(Circle[] circleArr) {
double sumArea = 0;
for (int i = 0; i < circleArr.length; i++) {
sumArea = sumArea + circleArr[i].getArea();
}
return sumArea;
}
}
public class Array3 {
public static void main(String[] args) {
Circle[] circleArr = new Circle[2];
circleArr[0] = new Circle(10);
circleArr[1] = new Circle(10);
double areas = Circle.getArrArea(circleArr);
System.out.println(areas); // 해당 넓이 출력
}
}
아래가 18이 나오도록 getStrArr 함수를 만드시오.
String[] strArr = new String[3]; strArr[0] = "ABCDER"; strArr[1] = "ABCDER"; strArr[3] = "ABCDER"; System.out.println(getStrArr(strArr));
public class AutoCallString {
public static void main(String[] args) {
String[] strArr = new String[3];
strArr[0] = "ABCDER";
strArr[1] = "ABCDER";
strArr[2] = "ABCDER";
System.out.println(getStrArr(strArr));
}
public static int getStrArr(String[] strArr) {
int cnum = 0;
for (int i = 0; i < strArr.length; i++) {
cnum += strArr[i].length();
}
return cnum;
}
}
class Rectangle {
private double w;
private double h;
public Rectangle(double w, double h) {
this.w = w;
this.h = h;
}
public double getArea() {
return (w * h);
}
public static double getArrArea(Rectangle[] recArr) {
double sumArea = 0;
for (int i = 0; i < recArr.length; i++) {
sumArea = sumArea + recArr[i].getArea();
}
return sumArea;
}
}
public class Array4 {
public static void main(String[] args) {
Rectangle[] recArr = new Rectangle[2];
recArr[0] = new Rectangle(10, 20);
recArr[1] = new Rectangle(10, 30);
double areas = Rectangle.getArrArea(recArr);
System.out.println(areas);
}
}