java抽象类和抽象方法实验报告

课程名称实验名称学生学号实验目的：

实验报告面向对象程序设计实验五、抽象类和抽象方法姓名

日期 2018-4-28班级通过本次实验，要求学生能进一步掌握抽象 类和抽象方法的概念，熟练义抽象类和抽象方法。实验条件：电脑一台、能上网查阅资料。首先定义基本几何图形的抽象基类（ Shape），然后定义Shape的派生类Circle(圆形)、Square（正方形）和Triangle(三角形)。要求通过抽象方法方法覆盖来计算各种图形的面积和周长。 (提示:求三角形的面积用海伦公式：S L*(La)*(Lb)*(Lc)，其中a,b,c是三角形的边长，L=(a+b+c)/2)，即周长的一半。)源代码：packageShape;publicabstractclassShape{protectedStringname;publicShape(){name="图形类";}publicShape(Stringname){super();=name;}publicStringgetName(){returnname;}publicvoidsetName(Stringname){=name;}abstractdoublearea();abstractdoublelength();publicStringtoString(){//TODOAuto-generatedmethodstubreturnname+"周长是："+length()+","+"面积是："+area();}packageShape;publicclassCircleextendsShape{privatedoubler;publicCircle(doubler,Stringname){super(name);this.r=r;}publicdoublegetR(){returnr;}publicvoidsetR(doubler){this.r=r;}doublearea(){//TODOAuto-generatedmethodstubreturnMath.PI*Math.pow(r,2);}doublelength(){//TODOAuto-generatedmethodstubreturnMath.PI*r*2;}}packageShape;publicclassSquareextendsShape{privatedoublea;publicSquare(doublea,Stringname){super(name);this.a=a;}publicdoublegetA(){returna;}publicvoidsetA(doublea){this.a=a;}doublearea(){//TODOAuto-generatedmethodstubreturnMath.pow(a,2);}doublelength(){//TODOAuto-generatedmethodstubreturn4*a;}packageShape;publicclassTriangleextendsShape{privatedoublea;privatedoubleb;privatedoublec;publicTriangle(doublea,doubleb,doublec,Stringname){super(name);this.a=a;this.b=b;this.c=c;}publicdoublegetA(){returna;}publicvoidsetA(doublea){this.a=a;}publicdoublegetB(){returnb;}publicvoidsetB(doubleb){this.b=b;}publicdoublegetC(){returnc;}publicvoidsetC(doublec){this.c=c;}doublearea(){//TODOAuto-generatedmethodstubdoublel=(a+b+c)/2;returnMath.sqrt(l*(l-a)*(l-b)*(l-c));}doublelength(){//TODOAuto-generatedmethodstubreturna+b+c;}}packageShape;publicclassDemo{publicstaticvoidmain(String[]args){Shapes1=null;s1=newCircle(5,"圆形");System.out.println(s1.toString());s1=newSquare(6,"正方形");System.out.println(s1.toString());s1=newTriangle(3,4,5,"三角形");System.out.println(s1.