Circle circle = new Circle(); circle.setRadius(10); double area = circle.getArea(); System.out.println(area); Rectangle rectangle = new Rectangle(); rectangle.setWidth(10); rectangle.setHeight(10); area = rectangle.getArea(); System.out.println(area); //100
public class Circle {
double radius;
double area;
final double PI = 3.14;
void setRadius(int num) {
radius = num;
}
double getArea() {
area = radius * radius * PI;
return area;
}
public static void main(String[] args) {
Circle circle = new Circle();
circle.setRadius(10);
double area = circle.getArea();
System.out.println(area);
Rectangle rectangle = new Rectangle();
rectangle.setWidth(10);
rectangle.setHeight(10);
area = rectangle.getArea();
System.out.println(area); // 100
}
}
class Rectangle {
double width;
double height;
double area;
void setWidth(int a)
{
width = a;
}
void setHeight(int b)
{
height = b;
}
double getArea() {
area = width * height;
return area;
}
}
class Circle { final double PI = 3.14; double radius; void setRadius(double num) { radius = num; } double getArea() { double area = radius * radius * PI; return area; } }
Rectangle rec = new Rectangle(); public class Rectangle { int height; int width; public int getHeight() { return height; } public void setHeight(int height) { this.height = height; } public int getWidth() { return width; } public void setWidth(int width) { this.width = width; } public int getArea() { return width * height; } }
📌 클래스(Class)
📌 객체(Object)
📌 인스턴스(Instance)
- 1 부터 num 까지 합을 구하는 class 를 작성하도록 하시오.
package classprac;
public class ClassSum {
public static void main(String[] args) {
Sum go = new Sum();
go.setEnd(10);
int sum = go.getSum();
System.out.println(sum);
go.setEnd(5);
sum = go.getSum();
System.out.println(sum);
}
}
class Sum {
int end;
int sum = 0;
void setEnd(int num) {
end = num;
}
int getSum() {
sum = 0;
for (int i = 1; i <= end; i++) {
sum += i;
}
return sum;
}
}
StraPrint strPrint = new StarPrint(); strPrint.printTriangle(3); System.out.println(); - 출력결과 - * ** ***
public class StarClass {
public static void main(String[] args) {
StarPrint strPrint = new StarPrint();
strPrint.printTriangle(3);
System.out.println();
}
}
class StarPrint {
int i;
int j;
void printTriangle(int a) {
for (i = 1; i <= a; i++) {
for (j = 1; j <= i; j++) {
System.out.print("*");
}
System.out.println();
}
}
}