8、通过Math类如何获取1-100之间的随机数？
(int)(Math.random()*100)+1
9、需求：定义一个长方形类,定义求周长和面积的方法，然后定义一个测试类进行测试。
public class Rectangle {
private int length;//长
private int width;//宽
//无参构造函数
public Rectangle() {
}
//有参构造函数
public Rectangle(int length, int width) {
this.length = length;
this.width = width;
}
//获得周长
public int getPerimeter() {
return (this.length+this.width)*2;
}
//获得面积
public int getArea() {
return this.length*this.width;
}
//get/set方法
public int getLength() {
return length;
}
public void setLength(int length) {
this.length = length;
}
public int getWidth() {
return width;
}
public void setWidth(int width) {
this.width = width;
}
public static void main(String[] args) {
Rectangle rectangle=new Rectangle(12,15);//创建长方形对象
int perimeter=rectangle.getLength();//获得周长
int area=rectangle.getArea();//获得面积
System.out.println("周长:"+perimeter+",面积:"+area);//输出结果
}
}
需求三：
人类Person
属性:姓名name,年龄age,性别gender
行为:学习study,睡觉sleep
public class Person {
private String name;//姓名
private int age;//年龄
private char gender;//性别
//无参构造函数
public Person() {
}
//有参构造函数
public Person(String name, int age, char gender) {
this.name = name;
this.age = age;
this.gender = gender;
}
//学习
public void study() {
System.out.println(this.name+"学习");
}
//睡觉
public void sleep() {
System.out.println(this.name+"睡觉");
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public char getGender() {
return gender;
}
public void setGender(char gender) {
this.gender = gender;
}
public static void main(String[] args) {
Person person=new Person("lss",15,'男');//创建Person对象
person.study();//学习
person.sleep();//睡觉
System.out.println("**********************");
Person person2=new Person();//创建Person对象
person2.setName("sada");//设置名字
person2.setAge(20);//设置年龄
person2.setGender('女');//设置性别
person2.study();//学习
person2.sleep();//睡觉
}
}