java抽象類和抽象方法實驗報告

課程名稱實驗名稱學生學號實驗目的：

實驗報告面向?qū)ο蟪绦蛟O計實驗五、抽象類和抽象方法姓名

日期 2018-4-28班級通過本次實驗，要求學生能進一步掌握抽象 類和抽象方法的概念，熟練義抽象類和抽象方法。實驗條件：電腦一臺、能上網(wǎng)查閱資料。首先定義基本幾何圖形的抽象基類（ Shape），然后定義Shape的派生類Circle(圓形)、Square（正方形）和Triangle(三角形)。要求通過抽象方法方法覆蓋來計算各種圖形的面積和周長。 (提示:求三角形的面積用海倫公式：S L*(La)*(Lb)*(Lc)，其中a,b,c是三角形的邊長，L=(a+b+c)/2)，即周長的一半。)源代碼：packageShape;publicabstractclassShape{protectedStringname;publicShape(){name="圖形類";}publicShape(Stringname){super();=name;}publicStringgetName(){returnname;}publicvoidsetName(Stringname){=name;}abstractdoublearea();abstractdoublelength();publicStringtoString(){//TODOAuto-generatedmethodstubreturnname+"周長是："+length()+","+"面積是："+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,"圓形");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.