statictest.java

来自「实验 1 对象的创建和使用 ( l ）理解类的定义； ( 2 ）掌握对象的」· Java 代码 · 共 58 行

//StaticTest．java
class Circle {
	static double pi = 3.14;

	static int objectNo = 0;

	int radius;

	Circle(int r) {
		radius = r;
		objectNo++;
	}

	Circle() {
		radius = 2;
		objectNo++;
	}

	double getArea() {
		return pi * radius * radius;
	}

	static void setPI(double p) {
		pi = p;
	}

	void setRadius(int r) {
		radius = r;
	}

	static void displayNo() {
		System.out.println("当前圆对象个数是：" + objectNo);
	}
}

public class StaticTest {
	public static void main(String args[]) {
		Circle cir1 = new Circle(5);
		System.out.println("cir1圆周率是：" + cir1.pi);
		System.out.println("cif1的半径是：" + cir1.radius);
		System.out.println("cir1的面积是：" + cir1.getArea());
		cir1.displayNo();
		cir1.setRadius(10);
		Circle cir2 = new Circle();
		cir2.setPI(3.1415);
		System.out.println("cirl圆周率是：" + cir1.pi);
		System.out.println("cirl的半径是：" + cir1.radius);
		System.out.println("cir2的半径是：" + cir2.radius);
		System.out.println("cir2的面积是：" + cir2.getArea());
		cir2.displayNo();
		Circle cirs[]=new Circle[5];
		for(int i=0;i<cirs.length;i++){
			cirs[i]=new Circle();
			cirs[i].displayNo();
		}
	}
}