一.代码：

java">public class Sain {private double yibian;private double erbian;private double sanbian;public Sain(double yibian,double erbian,double sanbian){  //初始化用逗号逗号逗号this.yibian=yibian;this.erbian=erbian;this.sanbian=sanbian;                                  //这是在干嘛，没有初始化怎么用，啊啊啊啊}public double SJXZC(){return yibian + erbian+sanbian;}                                                      //用了初始化之后类方法不用thispublic double SJXMJ(){double p=SJXZC()/2;                    //调用上面的类方法 直接类方法名字+（）double ara=Math.sqrt(p*(p-yibian)*(p-erbian)*(p-sanbian));  //开平方使用return ara;}public static void main(String[] args){  //写完函数之后，开始调用类来实现三角形Sain SJX =new Sain(3,4,5);    //用文件名来输入数值double Mj = SJX.SJXMJ();    //调用类方法System.out.println(Mj);double Zc=SJX.SJXZC();System.out.println(Zc);}}

二.收获：

再次熟悉类，注意看注释。