實驗10多態(tài)一

1、內(nèi)蒙古科技大學(xué)信息工程學(xué)院計算機系面向?qū)ο蟪绦蛟O(shè)計實驗報告姓名張國強學(xué)號1667159127班級軟件一班實驗日期第 17周（星期 三 ）6月 21 日第 一節(jié)項目號、實驗名稱實驗10 多態(tài)（一）實驗要求（任課教師提供）一、實驗?zāi)康?理解靜態(tài)聯(lián)編和動態(tài)聯(lián)編的概念；2理解掌握成員函數(shù)方式運算符重載；3理解掌握友元函數(shù)方式運算符重載；4理解掌握+、-、=運算符的重載。二、實驗內(nèi)容 2.1練習（一）：1理解下面的程序，并在VC+6.0下運行查看結(jié)果，回答程序后面的問題。#include "iostream.h"class CComplexpublic:CComplex()real

2、= 0; imag = 0;CComplex(int x,int y)real = x;imag = y;int real;int imag;CComplex operator + (CComplex obj1)-CComplex obj2(real + obj1.real, imag + obj1.imag);return obj2;void main()CComplex obj1(100,30);CComplex obj2(20, 30);CComplex obj;obj = obj1+obj2; -cout << obj.real <<endl;cout <

3、< obj.imag << endl;問題一：處的運算符重載，為什么該函數(shù)的返回值要設(shè)計成CComplex類型？問題二：處的運算符重載函數(shù)調(diào)用就相當于“obj=operator+(obj1,obj2);”，但是為什么CComplex類中的運算符重載函數(shù)只設(shè)計了一個參數(shù)？2理解下面的程序，并在VC+6.0下運行查看結(jié)果，回答程序后面的問題。#include "iostream.h"class CComplexpublic:CComplex()real = 0.0; imag = 0.0;CComplex(float x, float y)real = x;i

4、mag = y;CComplex operator + (CComplex &obj1, CComplex &obj2)CComplex obj3(obj1.real + obj2.real, obj1.imag + obj2.imag);return obj3;CComplex &operator+(CComplex &obj)obj.real += 1;obj.imag +=1;return obj;void print()cout<<real<<"+"<<imag<<"i&quo

5、t;<<endl;private:float real;float imag;CComplex &operator-(CComplex &x)x.real -= 1;x.imag -= 1;return x;void main()CComplex obj1(2.1,3.2);CComplex obj2(3.6,2.5);cout<<"obj1="obj1.print();cout<<"obj2="obj2.print();CComplex obj3 = obj1 + obj2;cout<<&

6、quot;befor+, obj3="obj3.print();+obj3;cout<<"after+, obj3="obj3.print();-obj3;cout<<"after-, obj3="obj3.print();CComplex obj4 = +obj3;cout<<"obj4="obj4.print();問題一：以上程序中的三個運算符重載都有錯誤，試改正過來，并分析該程序的輸出結(jié)果。2.2練習（二）：1把2.1中第一道題的程序改造成采取友元函數(shù)重載方式來實現(xiàn)“+”運算符，并采

7、取友元函數(shù)重載方式增加前置和后置“+”以及“-”運算符重載，并設(shè)計主函數(shù)來驗證重載運算符的用法。實驗內(nèi)容（由學(xué)生填寫）實驗一：問題一：處的運算符重載，為什么該函數(shù)的返回值要設(shè)計成CComplex類型？問題二：處的運算符重載函數(shù)調(diào)用就相當于“obj=operator+(obj1,obj2);”，但是為什么CComplex類中的運算符重載函數(shù)只設(shè)計了一個參數(shù)？回答：處obj = obj1+obj2; 相當于obj=obj1.operator+(obj2)，因為obj是CComplex類型，而返回值正是obj所以返回值要設(shè)計成CComplex類型。處 因為此函數(shù)是類內(nèi)的成員函數(shù)，有一個隱含的this

8、指針，所以只需一個參數(shù)就可以。試驗二： 第一個錯誤：如果重載+運算符且函數(shù)有兩個參數(shù)，則只能聲明為類的友元函數(shù)，不能聲明為類的成員函數(shù)。第二個錯誤：重載單目運算符+為類的成員函數(shù)，不需要參數(shù)。因為它的操作數(shù)是函數(shù)調(diào)用者。第三個錯誤：單目運算符函數(shù)沒有在類內(nèi)聲明，如果想要傳參，則必須將此函數(shù)聲明為類的友元函數(shù)。修改以后代碼如下：#include<iostream>using namespace std;class CComplexpublic:CComplex()real = 0.0;imag = 0.0;CComplex(float x, float y) real = x;ima

9、g = y;friend CComplex operator + (CComplex &obj1, CComplex &obj2);CComplex & operator+()real += 1;imag +=1;return *this;CComplex & operator-() real -= 1;imag -= 1;return *this;void print()cout<<real<<"+"<<imag<<"i"<<endl;private:float

10、 real;float imag;CComplex operator + (CComplex & obj1, CComplex & obj2) CComplex obj3(obj1.real + obj2.real, obj1.imag + obj2.imag);return obj3;int main()CComplex obj1(2.1,3.2);CComplex obj2(3.6,2.5);cout<<"obj1="obj1.print();cout<<"obj2="obj2.print();CComplex

11、 obj3 = obj1 + obj2;cout<<"befor+, obj3="obj3.print();+obj3;cout<<"after+, obj3="obj3.print();-obj3;cout<<"after-, obj3="obj3.print();CComplex obj4 = +obj3;cout<<"obj4="obj4.print();實驗三：代碼如下：#include<iostream>using namespace std;c

12、lass CComplexpublic:CComplex()real = 0;imag = 0;CComplex(int x,int y)real = x;imag = y;friend CComplex operator +(CComplex x1,CComplex x2);friend CComplex operator +(CComplex &x);friend CComplex operator +(CComplex &x,int); friend CComplex operator -(CComplex &x); friend CComplex operato

13、r -(CComplex &x,int); void print1() cout<<"相加結(jié)果(real,imag)="<<"("<<real<<","<<imag<<")"<<endl; void print2()cout<<"real="<<real<<" "cout<<"imag="<<imag<

14、;<endl;private:int real;int imag; CComplex operator +(CComplex x1,CComplex x2) CComplex x3(x1.real + x2.real, x1.imag + x2.imag); return x3; CComplex operator +(CComplex &x) x.real +; x.imag +; return x; CComplex operator +(CComplex &x,int) CComplex t=x; x.real +; x.imag +; return t; CCom

15、plex operator -(CComplex &x) x.real -; x.imag -; return x; CComplex operator -(CComplex &x,int) CComplex t=x; x.real -; x.imag -; return t; int main()CComplex obj1(100,30);CComplex obj2(20, 30);CComplex obj3= obj1+obj2;CComplex obj4(100,30);CComplex obj5(100,30);obj3.print1();cout<<&qu

16、ot;obj4后置+以后："(obj4+).print2(); cout<<"obj4后置-以后：" (obj4-).print2();cout<<"obj5前置+以后："(+obj5).print2();cout<<"obj5前置-以后："(-obj5).print2();聲明為類的成員函數(shù)實驗一二都涉及到，這里重點說一下單目運算符+的前置與后置。前置單目運算符和后置單目運算符的最主要區(qū)別是函數(shù)的形參，后置單目運算符帶一個int 型的參數(shù)，但它只起區(qū)分作用。實驗總結(jié)（由學(xué)生填寫）老師問試驗二錯誤的原因回答：第一個錯誤：如果重載+運算符且函數(shù)有兩個參數(shù)，則只能聲明為類的友元函數(shù)，不能聲明為類的成員函數(shù)。第二個錯誤：重載單目運算符+為類的成員