第四章部分作业

class Circle{double radius;double getArea(){double area=3.14*radius*radius;return area;}}public class Example4_2 {public static void main(String args[]){Circle circle;circle=new Circle();circle.radius=163.16;double area=circle.getArea();System.out.printf("半径是%5.3f的圆的面积：\n%5.3f\n",circle.radius,area);}}

class Lader{double above,bottom,height;Lader(){}Lader(double a,double b,double h){above = a;bottom = b;height = h;}public void setAbove(double a){above = a;}public void setBottom(double b){bottom = b;}public void setHeight(double h){height = h;}public double getArea(){return (above+bottom)*height/2;}}public class Example4_1 {public static void main(String[] args) {double area1=0,area2=0;Lader laderOne,laderTwo;laderOne = new Lader();laderTwo = new Lader(10,88,20);laderOne.setAbove(16);laderOne.setBottom(26);laderOne.setHeight(100);laderTwo.setAbove(300);laderTwo.setBottom(500);area1=laderOne.getArea();area2=laderTwo.getArea();System.out.println("laderOne的above和height:"+laderOne.above+","+laderOne.bottom+"," +laderOne.height);System.out.println("laderOne的面积："+area1);System.out.println("laderTwo的above和height:"+laderTwo.above+","+laderTwo.bottom+"," +laderTwo.height);System.out.print("laderTwo的面积："+area2);}}

class Lader{double above,height;static double bottom;void setAbove(double a){above = a;}void setBottom(double b){bottom = b;}double getAbove(){return above;}double getBottom(){return bottom;}}public class Example4_4 {public static void main(String[] args) {Lader.bottom=60;Lader laderOne,laderTwo;System.out.println("现在所有Lader对象的bottom都是"+Lader.bottom);laderOne=new Lader();laderTwo=new Lader();System.out.println("laderOne的bottom都是"+laderOne.getBottom());System.out.println("laderTwo的bottom都是"+laderTwo.getBottom());laderOne.setAbove(11);laderTwo.setAbove(22);laderTwo.setBottom(100);System.out.println("现在所有Lader对象的bottom都是"+Lader.bottom);System.out.println("laderOne的above都是"+laderOne.getAbove());System.out.println("laderTwo的above都是"+laderTwo.getAbove());}}

class Tom{final int MAX = 100;static final int MIN = 20;}public class Example4_5{public static void main(String args []){System.out.println(Tom.MIN);Tom cat = new Tom();int x = 0;x = Tom.MIN+cat.MAX;System.out.println(x);}}

class Computer{double x,y;static double max(double a,double b){return a>b?a:b;}}public class Example4_6 {public static void main(String[] args) {double max=Computer.max(12,45);System.out.print(max);}}