矩形的面积

package com.hanqi;
class juXing{
int chang;
int kuan;

public juXing(int chang,int kuan){
this.chang=chang;
this.kuan=kuan;

}
public double mianJi(){
return chang*kuan;
}
}
public class test03 {

public static void main(String[] args) {
juXing s=new juXing(10,20);
System.out.println(s.mianJi());

}

}