《Java程序设计》实验报告（二）之面向对象编程基础

实验内容及步骤：

编写不带构造函数的类并测试。（学生类、圆类）

（1）代码：

class Student {

String name="张三";

int age=20;

String sex="男";//gender

String getName(){

return name;

}

void setName(String newName)

{

name=newName;

}

void read()

{

System.out.println("我是"+name+"年龄："+age+",我正在学习！");

}

void c(Student student)

{

student.name="王琳";

student.age=200;

student.sex="male";

}

public static void main(String[] args)

{

Student student=null;

student=new Student();

System.out.println(student);

student.read();

Student student1=new Student();

实验内容及步骤：

System.out.println(student1);

student1.read();

Student student2=student;

System.out.println(student2);

}

Test:

public class Test

{

public static void main(String[] args)

{

Student student=new Student();

Student s=new Student();

student.name="李四";

student.setName("李四");

student.age=22;

student.sex="女";

System.out.println(student.getName());

student.read();

student.c(student);

student.read();

s.name="张三";

s.age=100;

s.sex="female";

student=s;

student.read();

s.read();

}

（2）运行结果：

编写带构造函数的类。（学生类、圆类）

（1）代码：

实验内容及步骤：

public class Circle

{

private double radius;

// 构造函数

public Circle(double radius)

{

this.radius = radius;

}

public double getRadius()

{

return radius;

}

public double getDiameter()

{

return 2 * radius;

}

public double getCircumference()

{

return 2 * Math.PI * radius;

}

public double getArea()

{

return Math.PI * radius * radius;

}

Test:

public class Test {

public static void main(String[] args) {

Circle circle = new Circle(5.0);

System.out.println("圆的半径：" + circle.getRadius());

System.out.println("圆的直径：" + circle.getDiameter());

System.out.println("圆的周长：" + circle.getCircumference());

System.out.println("圆的面积：" + circle.getArea());

}

（2）运行结果：

实验内容及步骤：

编写有静态方法的类。（求最大值、求和）

（1）代码：

public class MathUtils

{

public static int findMax(int[] numbers)

{

if (numbers == null || numbers.length == 0)

{

throw new IllegalArgumentException("数组不能为空");

}

int max = numbers[0];

for (int i = 1; i < numbers.length; i++)

{

if (numbers[i] > max)

{

max = numbers[i];

}

return max;

}

public static int sum(int[] numbers)

{

if (numbers == null || numbers.length == 0)

{

throw new IllegalArgumentException("数组不能为空");

}

int sum = 0;

for (int number : numbers)

{

sum += number;

实验内容及步骤：

}

return sum;

}

Test:

public class Test {

public static void main(String[] args) {

int[] numbers = {2, 5, 1, 8, 4};

int maxValue = MathUtils.findMax(numbers);

System.out.println("最大值：" + maxValue);

int sumValue = MathUtils.sum(numbers);

System.out.println("求和结果：" + sumValue);

}

运行结果：

4、编写对包操作的程序。（学生类及测试类分别放到两个包里）

（1）代码：

public class Student
{
    private String name;
    private int age;
    public Student(String name, int age)
    {
        this.name = name;
        this.age = age;
    }
    public String getName()
    {
        return name;
    }
    public void setName(String name)
    {
        this.name = name;
    }
    public int getAge()
    {

实验内容及步骤：

return age;

}
    public void setAge(int age)
    {
        this.age = age;
    }
}

Test:

public class Test {
    public static void main(String[] args) {
        Student person1 = new Student("张三", 20);
        System.out.println("姓名：" + person1.getName());
        System.out.println("年龄：" + person1.getAge());
        Student person2 = new Student("李四", 25);
        System.out.println("姓名：" + person2.getName());
        System.out.println("年龄：" + person2.getAge());
    }
}