Java继承性练习

Java继承性练习（一）

练习一

1.定义一个ManKind类，包括成员变量int sex和int salary；方法void manOrWoman()：根据sex的值显示“man”(sex==1)或者“woman”(sex==0)；方法void employeed()：根据salary的值显示“no job”(salary==0)或者“ job”(salary!=0)。

ManKind.java

public class ManKind {private int sex;// 性别private int salary;// 薪资public ManKind() {}public ManKind(int sex, int salary) {this.sex = sex;this.salary = salary;}public int getSex() {return sex;}public void setSex(int sex) {this.sex = sex;}public int getSalary() {return salary;}public void setSalary(int salary) {this.salary = salary;}/*** * @Description 根据sex的值显示“man”(sex==1)或者“woman”(sex==0)；* @author Zhkey* @data 2020年11月23日*/public void manOrWoman() {if (sex == 1)System.out.println("man");else if (sex == 0)System.out.println("woman");}/*** * @Description 根据salary的值显示“no job”(salary==0)或者“ job”(salary!=0)。* @author Zhkey* @data 2020年11月23日*/public void employeed() {if (salary == 0)System.out.println("no job");elseSystem.out.println("job");}
}

2.定义类Kids继承ManKind，并包括成员变量int yearsOld；方法printAge()打印yearsOld的值。

Kids.java

public class Kids extends ManKind {private int yearsOld;public Kids() {}public Kids(int yearsOld) {this.yearsOld = yearsOld;}public void printAge() {System.out.println("I am " + yearsOld + "years old!");}public int getYearsOld() {return yearsOld;}public void setYearsOld(int yearsOld) {this.yearsOld = yearsOld;}
}

3.定义类KidsTest，在类的main方法中实例化Kids的对象someKid，用该对象访问其父类的成员变量及方法。

KidsTes.java

public class KidsTest {public static void main(String[] args) {Kids someKids = new Kids(12);someKids.printAge();someKids.setSex(1);someKids.setSalary(0);someKids.employeed();someKids.manOrWoman();}
}

练习二

根据下图实现类。在CylinderTest类中创建Cylinder类的对象，设置圆
柱的底面半径和高，并输出圆柱的体积。

Circle,java

public class Circle {private double radius;public Circle() {radius = 1;}public Circle(double radius) {this.radius = radius;}public void setRadius(double radius) {this.radius = radius;}public double findArea() {return Math.PI*radius*radius;}
}

Cylinder.java

public class Cylinder extends Circle {private double length;public Cylinder() {length =1;}public Cylinder(double length) {this.length = length;}public double getLength() {return length;}public void setLength(double length) {this.length = length;}public double findVolume() {return findArea() * length;}
}

CylinderTest.java

public class CylinderTest {public static void main(String[] args) {Cylinder cy = new Cylinder();cy.setRadius(2.1);cy.setLength(3.4);System.out.println("圆柱的体积为：" + cy.findVolume());System.out.println("底面圆的面积为：" + cy.findArea());}
}