代码运行不通, 我GOOGLE了, 说是没main方法, 事实上我是写了main的,求大虾看看, 先谢了!不是吝啬分, 是想留着多问几个问题, 不想用申请N个马甲, 不过我相信你们不是为了分才来论坛的。 : )
package study.javase.test;abstract class Shape {
public final double PI = 3.14;
public Shape() {
System.out.println("A shape was create.");
}
void draw() {
System.out.println("Draw a shape");
}
// abstract method
abstract double area();
}
//
class Circle extends Shape {
int xpos;
int ypos;
int radius;
public Circle() {
super();
}
public Circle(int x, int y, int r) {
super();
xpos = x;
ypos = y;
radius = r;
}
public void draw() {
System.out.println("draw a circle");
}
public double area() {
return PI*radius*radius;
}
}
//
class Rectangle extends Shape {
int left;
int top;
int width;
int height;
public Rectangle() {
super();
}
public Rectangle(int l, int t, int w, int h) {
super();
left = l;
top = t;
width = w;
height = h;
}
public double area() {
return width*height;
}
}
public class Abstract {
public static void main(String args[]) {
Shape rec = new Rectangle(0, 0, 40, 30);
System.out.println(rec.area());
rec.draw();
Shape sha = new Circle(120, 130, 50);
System.out.println(sha.area());
sha.draw();
}
}
package study.javase.test;abstract class Shape {
public final double PI = 3.14;
public Shape() {
System.out.println("A shape was create.");
}
void draw() {
System.out.println("Draw a shape");
}
// abstract method
abstract double area();
}
//
class Circle extends Shape {
int xpos;
int ypos;
int radius;
public Circle() {
super();
}
public Circle(int x, int y, int r) {
super();
xpos = x;
ypos = y;
radius = r;
}
public void draw() {
System.out.println("draw a circle");
}
public double area() {
return PI*radius*radius;
}
}
//
class Rectangle extends Shape {
int left;
int top;
int width;
int height;
public Rectangle() {
super();
}
public Rectangle(int l, int t, int w, int h) {
super();
left = l;
top = t;
width = w;
height = h;
}
public double area() {
return width*height;
}
}
public class Abstract {
public static void main(String args[]) {
Shape rec = new Rectangle(0, 0, 40, 30);
System.out.println(rec.area());
rec.draw();
Shape sha = new Circle(120, 130, 50);
System.out.println(sha.area());
sha.draw();
}
}
at study.javase.test.Abstract.main(Abstract.java:60)
at study.javase.test.Abstract.main(Abstract.java:60)
at study.javase.test.Abstract.main(Abstract.java:60)
A shape was create.
1200.0
Draw a shape
A shape was create.
7850.0
draw a circle