问题描述
以下为我练手的学生成绩查询代码段，共有两个类，一个是Score类，我想把它设为私有类，另一个为Manager类，Manager为Score类的友元。Score.h
#include <map>#include <string>#include <iostream>#ifndef SCORE_H#define SCORE_Hstruct Score{ friend class Manager; typedef std::map<std::string,double> scMap; typedef std::map<std::string,double>::value_type index;//pair类型 Score():scoreMap(){} Score(scMap &s):scoreMap(s){} Score(index &i){scoreMap.insert(i);} void updateScore(const std::string &,double);//根据科目修改成绩 bool insertScore(index newScore) {if((scoreMap.insert(newScore)).second==true) return true;else{ std::cout<<'this project’s score has existed!'<<std::endl; return false;} } double requeryScore(const std::string &)const; bool deleteSigleScore(const std::string &); std::map<std::string,double> scoreMap;};#endif
Score.cpp
#include 'StdAfx.h'#include <iostream>#include 'Manager.h'#include 'Score.h'void Score::updateScore(const std::string &pro,double newScore){ if(scoreMap.count(pro)) {scoreMap[pro]=newScore; } else {std::cout<<'This student’s '<<pro<<'don’t exist!'<<std::endl; }}double Score::requeryScore(const std::string & sc)const{ if(scoreMap.count(sc)) {double newScor=(*(scoreMap.find(sc))).second;return newScor; } else {std::cout<<'This student’s '<<sc<<'don’t exist!'<<std::endl;return 0; }}bool Score::deleteSigleScore(const std::string &spro){ if(scoreMap.erase(spro)) {return true; } elsereturn false;}
Manager.h
#pragma once#include <map>#include <string>#include <iostream>#include 'Score.h'#ifndef MANAGER_H#define MANAGER_Hclass Manager{ typedef std::map<std::string,Score> studentMap;public: //只添加学生，不添加成绩 bool add(const std::string &); //同时添加姓名以及成绩 bool add(const std::string &,Score::index); bool add(const std::string &,Score::scMap &); /*void insertScore(const std::string &,*/ bool deleteStu(const std::string &); bool deleteScore(const std::string &,const std::string &); bool updateName(const std::string &,const std::string &); bool updateScore(const std::string &,const std::string &,double); double querySingleScore(const std::string &,const std::string &); std::map<std::string,double> queryAllScore(const std::string &); private: std::map<std::string,Score> stuMap;};#endif
Manager.cpp
#include 'StdAfx.h'#include 'Manager.h'#include <iostream>#include <utility>#include <iostream>#include <map>bool Manager::add(const std::string &sname){ if(stuMap.count(sname)) {std::cout<<sname<<'has existed'<<std::endl;return false; } else {std::pair<std::string,Score> newP;newP.first=sname;newP.second=Score();stuMap.insert(newP); } }bool Manager::add(const std::string &sname,Score::index scor){ if(stuMap.count(sname)) {stuMap[sname].insertScore(scor);return true; } else {stuMap.insert(std::make_pair(sname,Score(scor)));return true; }}bool Manager::add(const std::string &sname,Score::scMap &sCore){ if(stuMap.count(sname)) {std::cout<<sname<<'has existed'<<std::endl;return false; } else {stuMap.insert(std::make_pair(sname,sCore));return true; }}bool Manager::deleteStu(const std::string &sname){ if(stuMap.erase(sname)) {std::cout<<sname<<'has delelted'<<std::endl;return true; } else {std::cout<<sname<<'delete fail'<<std::endl;return false; }}bool Manager::deleteScore(const std::string &sname,const std::string &project){ studentMap::iterator stu=stuMap.find(sname); if(stu!=stuMap.end()) {return (stu->second).deleteSigleScore(project); } else {return false; }}bool Manager::updateName(const std::string &oldName,const std::string &newName){ studentMap::iterator iter=stuMap.find(oldName); if(iter!=stuMap.end()) {add(newName,iter->second.scoreMap);return true; } else {std::cout<<oldName<<'did not existed'<<std::endl;return false; }}bool Manager::updateScore(const std::string &stuName,const std::string &projName,double newScore){ studentMap::iterator iter=stuMap.find(stuName); if(iter!=stuMap.end()) {iter->second.updateScore(projName,newScore);return true; } elsereturn false;}double Manager::querySingleScore(const std::string &sname,const std::string &proj){ studentMap::iterator iter=stuMap.find(sname); /*if(iter!=stuMap.end()) {*/double newScor=iter->second.requeryScore(proj);return newScor; /*}*/ }std::map<std::string,double> Manager::queryAllScore(const std::string &sname){ studentMap::iterator iter=stuMap.find(sname); return iter->second.scoreMap;}
主程序
#include 'stdafx.h'#include 'Manager.h'#include <iostream>#include <map>#include <utility>static enum choice{ Query, Delete, Update, Add};Manager manager;void queryN(){ std::cout<<'*******************'<<std::endl; std::cout<<'Please enter the name you want to query:'<<std::endl; std::string studentName,projectName; if(std::cin>>studentName) {std::cout<<'*******************'<<std::endl;std::cout<<'Please enter the project name you want to query'<<std::endl;while(std::cin>>projectName){ double tempScore=manager.querySingleScore(studentName,projectName); std::cout<<studentName<<'’s '<<projectName<<'is '<<tempScore<<std::endl;} } std::cin.clear();}void cmdDelete(){ //delete student std::cout<<'*******************'<<std::endl; std::cout<<'What’s info do you want to delete ?(0:Student,1:Student’s score)'<<std::endl; int i; std::string nameDele,projDele; std::cin>>i; switch(i) { case 0:std::cout<<'*******************'<<std::endl;std::cout<<'Please enter the name the student you want to delete'<<std::endl;while(std::cin>>nameDele){ if(manager.deleteStu(nameDele))std::cout<<nameDele<<'deleted'<<std::endl; elsestd::cout<<nameDele<<'deleted fail'<<std::endl;}break; case 1:std::cout<<'*******************'<<std::endl;std::cout<<'Please enter the name the student you want to delete'<<std::endl;while(std::cin>>nameDele){ std::cout<<'Please enter the project that you want to delete'<<std::endl; while(std::cin>>projDele) {if(manager.deleteScore(nameDele,projDele)) std::cout<<nameDele<<'’s'<<projDele<<'succeed'<<std::endl;else std::cout<<nameDele<<'’s'<<projDele<<'fail'<<std::endl; }}break; } std::cin.clear();}void updateInfo(){ std::cout<<'*******************'<<std::endl; std::cout<<'Please enter what info do you want to update?(0:stdudent’s name 1:score'<<std::endl; int i; std::string queryName,newName,projName; double newScore; std::cin>>i; switch(i) { case 0:std::cout<<'*******************'<<std::endl;std::cout<<'Please enter the name you want to update'<<std::endl;std::cin>>queryName;std::cout<<'*******************'<<std::endl;std::cout<<'Please enter new name'<<std::endl;std::cin>>newName;if(manager.updateName(queryName,newName)){ std::cout<<'*******************'<<std::endl; std::cout<<queryName<<' has changed to '<<newName<<std::endl;}else{ std::cout<<'*******************'<<std::endl; std::cout<<'change fail'<<std::endl;}break; case 1:std::cout<<'*******************'<<std::endl;std::cout<<'Please enter the name you want to update'<<std::endl;std::cin>>queryName;std::cout<<'*******************'<<std::endl;std::cout<<'Please enter project name you want to update'<<std::endl;std::cin>>projName;std::cout<<'*******************'<<std::endl;std::cout<<'Please enter the new score '<<std::endl;std::cin>>newScore;if(manager.updateScore(queryName,projName,newScore)){ std::cout<<'*******************'<<std::endl; std::cout<<queryName<<'’s'<<projName<<' has changed to '<<newScore<<std::endl;}else{ std::cout<<'*******************'<<std::endl; std::cout<<'change fail'<<std::endl;}break; } std::cin.clear();}void cmdAdd(){ std::string newName,newProj; double newScore; do{std::cout<<'*******************'<<std::endl;std::cout<<'Please enter the new name,enter ’q’ to finish'<<std::endl;std::cin>>newName;std::cout<<'*******************'<<std::endl;std::cout<<'Please enter the new project'<<std::endl;while(std::cin>>newProj){ std::cout<<'*******************'<<std::endl; std::cout<<'Please enter the new score'<<std::endl; if(std::cin>>newScore) {manager.add(newName,std::make_pair(newProj,newScore)); }} }while(std::cin&&newName!='q');}int _tmain(int argc, _TCHAR* argv[]){ int choiceInt; do{ std::cout<<'Please choose the function you want to do:'<<std::endl; std::cout<<'*******************'<<std::endl; std::cout<<'0:Query'<<std::endl<<'1:Delete'<<std::endl<<'2:Update'<<std::endl<<'3:Add'<<std::endl;std::cin>>choiceInt; switch(choiceInt) { case 0:queryN();std::cin.clear();break; case 1:cmdDelete();std::cin.clear();break; case 2:updateInfo();std::cin.clear();break; case 3:cmdAdd();std::cin.clear();break; } }while(std::cin); return 0; }
我是把Manager的数据成员定义成string-Score的Map容器，但是我想把Score设为私有类只有Manager类可访问，这样Score就不能作为容器的元素，设为指针？也不行啊。大神可以指导一下么？
问题解答
回答1：把Score类的声明作为private成员放在Manager类的声明里:
//Manager.hclass Manager{public: //some public declarationsprivate: class Score{ public: //public members private: //private members go here }; //std::map<std::string, Score*> someMap; typedef std::shared_ptr<Score> ScorePtr; std::map<std::string, ScorePtr> anotherMap;};
这样你的Manager类里的Score类就是私有的，当别人试图实例化一个Score编译器会报错：
Manager::Score score;//error, class Manager::Score is private
然后每次需要对这个Map进行insert的时候，你用std::make_shared<Score>包上一层传进去。
回答2：你把Score类挪到Manager类里面不就完了。
