构造方法的使用，求长方形的周长和面积

public class test1 {
private int length;
private int wideth;
public test1() {

}
public test1(int length,int wideth) {
this.length=length;
this.wideth=wideth;
}
public int zhouchang() {
return(length+wideth)*2;
}
public int area() {
return(length*wideth);
}
public void setLength(int length) {
this.length=length;
}
public int getLength() {
return this.length;
}
public int getWideth() {
return this.wideth;
}
public void setWideth(int wideth) {
this.wideth=wideth;
}
}

重新创建一个类，实现功能.

public class Demo5 {
public static void main(String[] args) {
test1 test1=new test1();
test1.setLength(20);
test1.setWideth(30);
System.out.println(test1.area());
System.out.println(test1.zhouchang());

}
}