C第8次實驗報告

1、c語言程序設(shè)計課程實驗報告（第8次）院：數(shù)學(xué)與計算機(jī)學(xué)院名：張元杰 號：201510804033 業(yè)：軟件工程 級：1班 人:實驗地點：6a-2實驗時間： 指導(dǎo)教師:實驗名稱：多態(tài)性與虛函數(shù)所使用的開發(fā)工具及環(huán)境：硬件pc機(jī)一臺 實驗?zāi)康?(1) 了解多態(tài)性的概念。(2) 了解虛函數(shù)的作用及使用方法。(3) 了解靜態(tài)關(guān)聯(lián)和動態(tài)關(guān)聯(lián)的概念和川法。(4) 了解純虛函數(shù)和抽象類的概念和用法。實驗內(nèi)容：1、分析程序運(yùn)行結(jié)果，掌握焜函數(shù)的使用。程序一：#include <iostream>using namespace std;class one public:virtual void f(

2、)cout«mone"«endl;)；class two:public one public:two() cout«,two,«endl;；class three:public two public:virtual void f()two:f(); coutvv“three”;；void main() one aa, *p;two bb; /twothree cc; /twop = & cc;p->f();/one three cout«e ndl;)程序二#inelude <iostream>using n

3、amespace std;class base public:virtual void fn() cout «nin base class'd;class subclass :public base public:virtual void fn() cout «"in sub classn" 覆蓋；void main()base be盧p;subclass sc;p=&bc;p->fn();/in base classp=&sc;p->fn();/in sub class)2、實現(xiàn)一個類a,在a中有兩個私有的整型變量a

4、和b,定義構(gòu)造函數(shù)對a和b進(jìn)行初 始化，并實現(xiàn)成員函數(shù)gda ()取得a的值和gclb ()取b的值。實現(xiàn)類b從a繼承， 覆蓋geta (),使其返冋a的2倍。主函數(shù)屮聲明類b對象，調(diào)用類b屮的geta ()并將 結(jié)果輸出。3、設(shè)計一個計算圖形面積的類庫。它的頂層是一個抽彖類，并且提供相應(yīng)的接口函數(shù)。 抽象基類shape,派生出point類、矩形rectangle、正方形square, point類派生出圓 形circleo要求：(1) 每個類有構(gòu)造函數(shù)、析構(gòu)函數(shù)，并有相應(yīng)的輸出語句，女ii： “正在構(gòu)造圓形”(2) 能顯示每個類的信息，如：輸出“我是圓形”(3) 能計算面積、周長(4) 定義

5、一個基類shape類型的指針，實現(xiàn)動態(tài)多態(tài)(5) 動態(tài)創(chuàng)建一個圓形對象，賦值給基類shape類型的指針變蜃，程序最示delete該 指針，保證析構(gòu)函數(shù)的正確調(diào)用(提示：虛析構(gòu)函數(shù))(6) 在主函數(shù)測試。4、設(shè)計一個基類base,其作用是計算一個圖形的面積，它只有一個公有的函數(shù)成員虛 函數(shù)area。再從base類公有派生一個三角形類triangle和一個圓類circle,在類 triangle和類circle中分別定義自己的area函數(shù)，用于計算各自的面積。在主函數(shù) 中設(shè)計一個base類的對象指針,分別指向類triangle和類circle的對象，調(diào)用各自 的area函數(shù)顯示相應(yīng) 對象的面積。分

6、析：用虛函數(shù)實現(xiàn)多態(tài)。5. 將上題中的base類改為抽象類，應(yīng)用抽象類，求矩形、圓形的周長和而積。分析：將base類的其成員函數(shù)area和perimeter聲明為純虛函數(shù)，base就成為一個 抽 象類。然后再從bose派生矩形類和圓形類，分別實現(xiàn)base屮純虛函數(shù)的功能.結(jié)果與分析:sy8-1:程序一：存 f:c+侮習(xí)ldebugl.exe程序二:sy8-2:#include<iostream> using namespace std; class apublic:a(int a,int b):a(a),b(b) virtual int geta()return a; friend

7、 class b;private:ini a;int b;class b:public apublic:b(int a,int b):a(a,b) int geta() return 2*a;)；int main()a *p=new b3);cout«p->geta()«endl; system(hpausen);return 0;f:c- #供撿實驗 8sy82debugsy82,exe脣按任意鍵繼續(xù)sy8-3:#in clude<iostream>using namespace std;const double pl=3.1415926;class s

8、hapepublic:shape()cout«nconstructing shape.h«endl;virtual -shapc()cout«ndcstructing shape.h«cndl;(virtual void name()cout«nsharen«endl;)virtual double area()=0;virtual double c()=0;；class point: public shapepublic:point()cout«hconstructing point.m«endl;point()

9、cout«mdestructing point.h«endl;virtual void name()cout«hpointn«endl;) double area() return ();double c() return 0;);class recta ng le:public shapepublic:rectangle(int ljnt w):length(l),width(w)cout«mconstructing rectangle.u«endl;-rectangleo cout«hdestructing recta

10、ngle.m«endl;double area() return length * width;double c() return (length+width)*2;)void name()cout«mrectangleh«endl;)private:double length;double width;);class squre:public shapepublic:squre(int 1):l(1)cout«nconstructing squre.m«endl;-squre()coul«ndestructing squre.,&#

11、171;endl;void name()cout«hsqurem«endl;double area() return l*l;double c() return 4*l;private:double l;class circle: public virtual pointpublic:circle(double r):radious(r) cout«mconstructing circle.h«endl;) circle()cout«ndestructing circle.h«endl;)void name() cout«m

12、circlelf«endl;double area() return pi*radious*radious;double c() return 2*pi*radious;private:double radious;int main()shape *p;p=new point;p->name();cout«',c:,«p->c()«endl;cout«marea:h«p->area()«endl;delete p;cout«endl;p=new recta ng le(2,3);p->

13、;name();cout«mc:h«p->c()«endl; cout«harca:h«p->arca()«cndl;delete p;cout«endl;p=new squre(4);p->name();cout«mc:m«p->c()«endl;cout«marea:h«p->area()«e ndl;delete p;cout«endl;p二new circle(5);p->name();cout«mc:

14、m«p->c()«endl; cout«marea:h«p->area()«endl;delete p;system(hpausen);af:c - 實埶實驗 8sy8 3debugsy8-3.execonstructing shape. constructing point. po intc：0area：0destructing point. destructing shape.constructing shape. constructing rectangle. rectanglec：10area： 6destructing r

15、ectangle. destructing shape.constructing shape. constructing squre. squrec：16area：16destructing squre. destructing shape.constructing constructing constructing circle c：31.4159 area：78.5398 destructing circle. destructing point. destructing shape. 請按任意鍵繼續(xù)sy8-4:#in clude<iostream>using namespac

16、e std;const double pl=3.1415926;class basepublic:base() cout«mconstrucling base.m«endl;virtual basc()cout«hdcstructcd basc.u«cndl;virtual double area()=();class triangleipublic basepublic:triangle(double a,double b,double c):a(a),b(b),c(c)cout«nconstructing triangle.n«e

17、ndl;-triangle() cout«hdestructed triangle.n«endl;double area()return sqrt(0.5*(a+b+c)*(0.5*(a+b+c)-a)*(0.5*(a+b+c)-b)*(0.5*(a+b+c)-c); private:double a、b,c;class circle:public basepublic:circle(double r):radious(r)cout«hconstructing circle.n«endl;-circle() cout«hdestructed c

18、ircle.u«endl;double area() return pi*radious*radious;private:double radious;int main()base *p;p=new triangle(3,4,5);cout«marea:h«p->area()«endl;delete p;cout«endl;p=ncw circlc(4);cout«marea:,r«p->area()«endl;delete p;cout«endl;system(mpausen);return

19、 0;f:ct- 實驗 實驗趴sy 8 -4debu gsy8-4.execonstructing base. constructing triangle. area：6destructed triangle. destructed base.constructing base. constructing circle. area：50.2655 destructed civcle. destructed base.sy8-5:#in clude<iostream>using namespace std;const double pl=3.1415926;class basepub

20、lic:base()cout«hconstructing base.m«endl;)virtual base()cout«ndestructed base.h«endl;virtual double area()=0;virtual double perimeter()=o; 周長);class triangle:public basepublic:triangle(double a,double b,double c):a(a),b(b),c(c)cout«nconstructing triangle.n«endl; triangl

21、e()cout«hdestructed triangle.m«endl;double area() return sqrt(0.5*(a+b+c)*(0.5*(a+b+c)-a)*(0.5*(a+b+c)-b)*(0.5*(a+b+c)-c); double perimeter() return a+b+c;private:double a,b,c;class circle:public basepublic:circle(double r):radious(r)cout«mconstructing circle.n«endl;)circle() cout«11 destruc