c++面向?qū)ο?實(shí)驗(yàn)7 多態(tài)與重載

中北大學(xué)計(jì)算機(jī)與控制工程學(xué)院實(shí)驗(yàn)報(bào)告課程名稱面向?qū)ο蟪绦蛟O(shè)計(jì)學(xué)號1507084143學(xué)生姓名劉安光輔導(dǎo)教師韓慧妍專業(yè)網(wǎng)絡(luò)工程實(shí)驗(yàn)室名稱軟件基礎(chǔ)實(shí)驗(yàn)室實(shí)驗(yàn)時(shí)間2016.11.301.實(shí)驗(yàn)名稱實(shí)驗(yàn)七多態(tài)和重載實(shí)驗(yàn)?zāi)康模?）掌握運(yùn)算符重載的方法（2）學(xué)習(xí)使用虛函數(shù)實(shí)現(xiàn)動(dòng)態(tài)多態(tài)性。實(shí)驗(yàn)內(nèi)容（1）定義Point類，有坐標(biāo)x，y兩個(gè)成員變量；對Point類重載“++”（自增）、“一一”（自減）運(yùn)算符，實(shí)現(xiàn)對坐標(biāo)值的改變。（2）定義一個(gè)車（vehicle）基類，有Run、Stop等成員函數(shù)，由此派生出自行車（bicycle）類、汽車（motorcar）類，從bicycle和motorcar派生出摩托車（motorcycle）類，它們都有Run、Stop等成員函數(shù)。觀察虛函數(shù)的作用。實(shí)驗(yàn)原理或流程圖運(yùn)算符重載（C++）一、運(yùn)算符重載機(jī)制：一元運(yùn)算符：@obj=>operator@（obj）；二元運(yùn)算符：obj@obj2=>operator@（obj,obj2）注意：后置++、--這樣處理：obj++=>operator++（obj,0）二、除了.、.*、：:、？:、sizeof這5個(gè)運(yùn)算符之外，其他一概都可以重載。三、普通運(yùn)算符重載：1.重載為類的友元函數(shù)；2.重載為類的成員函數(shù)；1）一般情況下，單目運(yùn)算符最好重載為類的成員函數(shù)；雙目運(yùn)算符則最好重載為類的友元函數(shù)。2）一些雙目運(yùn)算符不能重載為類的友元函數(shù)：=、（）、［］、->。3）若一個(gè)運(yùn)算符的操作需要改變對象的狀態(tài)，選擇重載為成員函數(shù)較好。4）若運(yùn)算符所需的操作數(shù)（尤其第一個(gè)操作數(shù)）希望有隱式類型轉(zhuǎn)換，則只能選用友元函數(shù)。5）當(dāng)運(yùn)算符函數(shù)是一個(gè)成員函數(shù)時(shí)，最左邊的操作數(shù)必須是運(yùn)算符類的一個(gè)類對象或其引用。若左邊的操作數(shù)必須是一個(gè)不同類的對象，或者是一個(gè)基本數(shù)據(jù)類型的對象，該運(yùn)算符函數(shù)必須作為一個(gè)友元函數(shù)來實(shí)現(xiàn)。6）當(dāng)需要重載運(yùn)算符的運(yùn)算具有可交換性時(shí)，選擇重載為友元函數(shù)。虛函數(shù)：虛函數(shù)是C++實(shí)現(xiàn)動(dòng)態(tài)單分派子類型多態(tài)（dynamicsingle-dispatchsubtypepolymorphism）的方式。動(dòng)態(tài)：在運(yùn)行時(shí)決定的（相對的是靜態(tài)，即在編譯期決定，如函數(shù)重載、模板類的非虛函數(shù)調(diào)用）單分派：基于一個(gè)類型去選擇調(diào)用哪個(gè)函數(shù)（相對于多分派，即由多個(gè)類型去選擇調(diào)用哪個(gè)函數(shù)）子類型多態(tài)：以子類型-超類型關(guān)系實(shí)現(xiàn)多態(tài)（相對于用參數(shù)形式，如函數(shù)重載、模版參數(shù)）實(shí)驗(yàn)過程或源代碼填寫實(shí)際上機(jī)操作的實(shí)驗(yàn)步驟或主要源代碼實(shí)驗(yàn)(1)//Point.hclassPoint{private:intx,y;public:Point(intx,inty);Point();Pointoperator++();Pointoperator++(int);Pointoperator--();Pointoperator--(int);voidprint();};//Point.cpp#include<iostream>#include"Point.h"usingnamespacestd;Point::Point(){}Point::Point(intx,inty){this->x=x;this->y=y;}PointPoint::operator++(){++x;++y;return*this;//返回自增后當(dāng)前對象的值}PointPoint::operator++(int){Pointteam(*this);x++;y++;returnteam;//返回自增前當(dāng)前對象的值}PointPoint::operator--(){--x;--y;return*this;//返回自減后當(dāng)前對象的值}PointPoint::operator--(int){Pointteam(*this);X--；y--；returnteam;//返回自減前當(dāng)前對象的值voidPoint::print(){cout<<"x:"<<x<<",y:"<<y<<endl;//main.cpp#include"Point.h"intmain(){Pointa(3,4);Pointb=a--;print();print();--a;a.print();a--;a.print();++a;a.print();a++;a.print();return0;實(shí)驗(yàn)(2)//vehicle.h#pragmaonceclassvehicle{private:doubleMaxSpeed;doubleWeight;public:virtualvoidRun();virtualvoidStop();};//vehicle.cpp#include<iostream>#include"vehicle.h"usingnamespacestd;voidvehicle::Run(){cout<<"Thisisvehicle'sRun"<<endl;}voidvehicle::Stop(){cout<<"Thisisvehicle'sStop"<<endl;}//bicycle.h#include"vehicle.h"classbicycle:virtualpublicvehicle{private:doubleheight;public:virtualvoidRun();virtualvoidStop();};//bicycle.cpp#include<iostream>#include"bicycle.h"usingnamespacestd;voidbicycle::Run(){cout<<"Thisisbicycle'sRun"<<endl;}voidbicycle::Stop(){cout<<"Thisisbicycle'sStop"<<endl;}//motorcar.h#include"vehicle.h"classmotorcar:virtualpublicvehicle{private:intSeatNum;public:virtualvoidRun();virtualvoidStop();};//motorcar.cpp#include<iostream>#include"motorcar.h"usingnamespacestd;voidmotorcar::Run(){cout<<"Thisismotorcar'sRun"<<endl;}voidmotorcar::Stop(){cout<<"Thisismotorcar'sStop"<<endl;}//motorcycle.h#include"bicycle.h"#include"motorcar.h"classmotorcycle:publicbicycle,publicmotorcar{private:public:virtualvoidRun();virtualvoidStop();};//motorcycle.cpp#include<iostream>#include"motorcycle.h"usingnamespacestd;voidmotorcycle::Run(){cout<<"Thisismotorcycle'sRun"<<endl;}voidmotorcycle::Stop(){cout<<"Thisismotorcycle'sStop"<<endl;}//main.cpp#include<iostream>#include"motorcycle.h"usingnamespacestd;intmain(){cout<<”各對象調(diào)用自己的成員函數(shù):"<<endl;vehicleche;che.Run();che.Stop();bicyclezixingche;zixingche.Run();zixingche.Stop();motorcarqiche;qiche.Run();qiche.Stop();motorcyclemotoche;motoche.Run();motoche.Stop();cout<<endl<<”用vehicle類型的指針來調(diào)用這幾個(gè)對象的成員函數(shù):"<<endl;vehicle*c;c=&zixingche;c->Run();c->Stop();c=&qiche;c->Run();c->Stop();c=&motoche;c->Run();c->Stop();return0;}實(shí)驗(yàn)結(jié)論及心得填寫本次實(shí)驗(yàn)的輸出結(jié)果（如果有輸出的話）、存在的問題、心得等內(nèi)容x:2,y:3x：3,y：4x:1,y:2x：0,y：lx:1,y:2x:2,y:3請矮任意鍵繼續(xù)...各計(jì)輯調(diào)用自己的成員函數(shù)：Thisisvehicle，sRunThisisvehicle，sStopThisisbicycle，sRunThisisbicycle，sStopThisismotorcar，sRunThisismotorcar，sStopThisismotorcycle1sRunThisismotorcycle1sStop用vehicle類裂的捐針來調(diào)用這幾個(gè)對象的成員函數(shù):Thisisvehicle，sRunThisisvehicle，sStopThisisvehicle，sRunThisisvehiclensStopThisisvehiclensRunThisisvehiclensStop請按任意鍵繼續(xù)....各計(jì)慝調(diào)用耳己即成員函數(shù)：Thisisvehicle，sRunThisisvehicle，sStopThisisbicycle，sRunThisisbicycle，sStopThisismotorcar1sRunThisismot