Java实验一 类的设计与对象使用
package ex1;
import java.util.Scanner;
class Circle{
private double radius = 0;
public Circle() {
}
public Circle(double radius) {
this.radius = radius;
}
public double getArea() {
return radius*radius*Math.PI;
}
}
class Trapezoid{
private double length1 = 0;
private double length2 = 0;
private double high = 0;
public Trapezoid() {
}
public Trapezoid(double length1, double length2, double high){
this.length1 = length1;
this.length2 = length2;
this.high = high;
}
public double getArea() {
return (length1+length2)*high/2;
}
}
public class Test {
public static void main(String[] args) {
Scanner stdIn = new Scanner(System.in);
System.out.println("-----Class Circle Test-----");
System.out.println("Please input the radius:");
double radius = stdIn.nextDouble();
Circle[] circleTest = new Circle[2];
circleTest[0] = new Circle();
circleTest[1] = new Circle(radius);
System.out.println("The area of the circle1 is: " + circleTest[0].getArea());
System.out.println("The area of the circle2 is: " + circleTest[1].getArea());
System.out.println("-----Class Trapezoid Test-----");
System.out.println("Please input the length1, length2, high in order:");
double[] a = new double[3];
for(int i=0; i<a.length; i++) {
a[i] = stdIn.nextDouble();
}
Trapezoid trapezoidTest = new Trapezoid(a[0], a[1], a[2]);
System.out.printf("The area of the Trapezozid is: %.2f", trapezoidTest.getArea());
}
}
运行结果
更新
四种实现方式
1.
package ex1; //第一次试验
import java.util.Scanner;
//继承实现
//抽象类Shape
abstract class Shape{
abstract public double getArea();
}
//Circle继承Shape
class Circle extends Shape{
private double radius = 0;
public Circle() {
}
public Circle(double radius) {
this.radius = radius;
}
public double getArea() {
return radius*radius*Math.PI;
}
}
//Trapezoid继承Shape
class Trapezoid extends Shape{
private double length1 = 0;
private double length2 = 0;
private double high = 0;
public Trapezoid() {
}
public Trapezoid(double length1, double length2, double high){
this.length1 = length1;
this.length2 = length2;
this.high = high;
}
public double getArea() {
return (length1+length2)*high/2;
}
}
//测试类
public class Test {
public static void main(String[] args) {
Scanner stdIn = new Scanner(System.in);
System.out.println("-----Class Circle Test-----");
System.out.println("Please input the radius:");
double radius = 0.0;
do {
radius = stdIn.nextDouble();
if(radius < 0) {
System.out.println("radius must > 0, please input again:");
}
}while(radius < 0);
Circle[] circleTest = new Circle[2];
circleTest[0] = new Circle();
circleTest[1] = new Circle(radius);
System.out.println("The area of the default circle1 is: " + circleTest[0].getArea());
System.out.println("The area of the circle2 is: " + circleTest[1].getArea());
System.out.println("-----Class Trapezoid Test-----");
System.out.println("Please input the length1, length2, high in order:");
double length1 = 0.0;
double length2 = 0.0;
double high = 0.0;
do {
length1 = stdIn.nextDouble();
length2 = stdIn.nextDouble();
high = stdIn.nextDouble();
if(length1<0 || length2<0 || high<0) {
System.out.println("Wrong!!! Please input again:");
}
}while(length1<0 || length2<0 || high<0);
Trapezoid trapezoidTest = new Trapezoid(length1, length2, high);
System.out.printf("The area of the Trapezozid is: %.2f", trapezoidTest.getArea());
stdIn.close();
}
}
package ex1;
import java.util.Scanner;
//接口实现
interface Shape1{
public double getArea();
}
class Circle1 implements Shape1{
private double radius = 0;
public Circle1() {
}
public Circle1(double radius) {
this.radius = radius;
}
public double getArea() {
return radius*radius*Math.PI;
}
}
class Trapezoid1 implements Shape1{
private double length1 = 0;
private double length2 = 0;
private double high = 0;
public Trapezoid1() {
}
public Trapezoid1(double length1, double length2, double high){
this.length1 = length1;
this.length2 = length2;
this.high = high;
}
public double getArea() {
return (length1+length2)*high/2;
}
}
public class Test1 {
public static void main(String[] args) {
Scanner stdIn = new Scanner(System.in);
System.out.println("-----Class Circle Test-----");
System.out.println("Please input the radius:");
double radius = 0.0;
do {
radius = stdIn.nextDouble();
if(radius < 0) {
System.out.println("radius must > 0, please input again:");
}
}while(radius < 0);
Circle1[] circleTest = new Circle1[2];
circleTest[0] = new Circle1();
circleTest[1] = new Circle1(radius);
System.out.println("The area of the default circle1 is: " + circleTest[0].getArea());
System.out.println("The area of the circle2 is: " + circleTest[1].getArea());
System.out.println("-----Class Trapezoid Test-----");
System.out.println("Please input the length1, length2, high in order:");
double length1 = 0.0;
double length2 = 0.0;
double high = 0.0;
do {
length1 = stdIn.nextDouble();
length2 = stdIn.nextDouble();
high = stdIn.nextDouble();
if(length1<0 || length2<0 || high<0) {
System.out.println("Wrong!!! Please input again:");
}
}while(length1<0 || length2<0 || high<0);
Trapezoid1 trapezoidTest = new Trapezoid1(length1, length2, high);
System.out.printf("The area of the Trapezozid is: %.2f", trapezoidTest.getArea());
stdIn.close();
}
}
package ex1;
import java.util.Scanner;
//直接用两个类实现
//圆类
class Circle2 {
private double radius = 0;
public Circle2() {
}
public Circle2(double radius) {
this.radius = radius;
}
public double getArea() {
return radius*radius*Math.PI;
}
}
//梯形类
class Trapezoid2 {
private double length1 = 0;
private double length2 = 0;
private double high = 0;
public Trapezoid2() {
}
public Trapezoid2(double length1, double length2, double high){
this.length1 = length1;
this.length2 = length2;
this.high = high;
}
public double getArea() {
return (length1+length2)*high/2;
}
}
public class Test2 {
public static void main(String[] args) {
Scanner stdIn = new Scanner(System.in);
System.out.println("-----Class Circle Test-----");
System.out.println("Please input the radius:");
double radius = 0.0;
do {
radius = stdIn.nextDouble();
if(radius < 0) {
System.out.println("radius must > 0, please input again:");
}
}while(radius < 0);
Circle2[] circleTest = new Circle2[2];
circleTest[0] = new Circle2();
circleTest[1] = new Circle2(radius);
System.out.println("The area of the default circle1 is: " + circleTest[0].getArea());
System.out.println("The area of the circle2 is: " + circleTest[1].getArea());
System.out.println("-----Class Trapezoid Test-----");
System.out.println("Please input the length1, length2, high in order:");
double length1 = 0.0;
double length2 = 0.0;
double high = 0.0;
do {
length1 = stdIn.nextDouble();
length2 = stdIn.nextDouble();
high = stdIn.nextDouble();
if(length1<0 || length2<0 || high<0) {
System.out.println("Wrong!!! Please input again:");
}
}while(length1<0 || length2<0 || high<0);
Trapezoid2 trapezoidTest = new Trapezoid2(length1, length2, high);
System.out.printf("The area of the Trapezozid is: %.2f", trapezoidTest.getArea());
stdIn.close();
}
}
package ex1;
import java.util.Scanner;
//一个Shape类用多态实现
//重载getArea()函数
class Shape3{
public Shape3() {
}
public double getArea(double radius) {
return Math.PI*radius * radius;
}
public double getArea(double length1, double length2, double high) {
return (length1+length2)*high/2;
}
}
public class Test3 {
public static void main(String[] args) {
Scanner stdIn = new Scanner(System.in);
System.out.println("-----Class Circle Test-----");
System.out.println("Please input the radius:");
double radius = 0.0;
do {
radius = stdIn.nextDouble();
if(radius < 0) {
System.out.println("Please input again:");
}
}while(radius < 0);
Shape3 a = new Shape3();
System.out.println("The area of the circle1 is: " + a.getArea(radius));
System.out.println("-----Class Trapezoid Test-----");
System.out.println("Please input the length1, length2, high in order:");
double length1 = 0.0;
double length2 = 0.0;
double high = 0.0;
do {
length1 = stdIn.nextDouble();
length2 = stdIn.nextDouble();
high = stdIn.nextDouble();
if(length1<0 || length2<0 || high<0) {
System.out.println("Wrong!!! Please input again:");
}
}while(length1<0 || length2<0 || high<0);
Shape3 b = new Shape3();
System.out.printf("The area of the Trapezozid is: %.2f", b.getArea(length1, length2, high));
stdIn.close();
}
}
结果
