我真的不知道，如何解释这个问题。但在这里...... 假设我有一个外部文本文件，其内容如下：
1 Crysis 2012 Crytek Ubisoft
2 FarCry 2009 Crytek Ubisoft
3 Need_For_Speed 1695 EA Ubisoft
4 Assassin'sCreed 2008 Ubisoft Ubisoft
5 COD 2010 Activision Ubisoft
然后我使用了这段代码：
if (fout.is_open())
{
std::string delim = " ";
size_t pos = 0;
std::string token;
while (getline(fout, line))
{
while ((pos = line.find(delim)) != std::string::npos)
{
token = line.substr(0, pos);
std::cout << token << std::endl;
line.erase(0, pos + delim.length());
}
std::cout << line << std::endl;
}
}
此代码拆分文本行并输出以下内容
1
Crysis
2012
Crytek
Ubisoft
2
FarCry
2009
Crytek
Ubisoft
3
Need_For_Speed
1695
EA
Ubisoft
4
Assassins'sCreed
2008
Ubisoft
Ubisoft
5
COD
2010
Activision
Ubisoft
我真正想要的是在每个循环中创建一个新结构并创建它的5个变量来保存每个游戏的每个属性。例如
struct Game
{
int id;
string title;
int year;
string developer;
string publisher;
};
现在来自输出：
1
Crysis
2012
Crytek
Ubisoft
当循环运行时，我想创建一个新的“游戏”结构，并将这些值分配给它的变量，然后将结构推入矢量。
以下是我想要创建的内容以及我已经走了多远：
该计划是一个游戏数据库。用户可以添加，删除，搜索和编辑数据库中的任何项目。当程序运行并且用户添加游戏时，它成功地在外部.txt文件中写入并且也被推送到向量的末尾。现在一切都很好。但是当我关闭程序并再次运行它时，文本文件中有数据，但向量为空。所以我希望使用.txt文件中的数据再次填充向量，以便用户可以继续使用数据库。
我不知道我是否足够好地解释了这个问题。或者我可能已经解释了它。我实际上是C ++中的菜鸟。
提前致谢..
这是我正在处理的程序的完整代码...
#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
using namespace std;
struct Game
{
int id;
int year;
string title;
string publisher;
string developer;
};
void ShowData(vector<Game> myDatabase)
{
cout << endl;
for(size_t i = 0; i <= myDatabase.size()-1; i++)
{
cout << endl;
cout << "-------------------------------------------------------"<<endl;
cout << " ITEM NO" << " " << i + 1 << " " <<endl;
cout << "-------------------------------------------------------"<<endl;
cout << " TITLE: " << myDatabase[i].title << endl;
cout << " YEAR: " << myDatabase[i].year << endl;
cout << "DEVELOPER: " << myDatabase[i].developer << endl;
cout << "PUBLISHER: " << myDatabase[i].publisher << endl;
}
}
int _tmain(int argc, _TCHAR* argv[])
{
string option;
int serialNumber = 0;
int count = 0;
string line;
vector<Game> Database;
fstream fout;
fout.open("Database.txt");
if (fout.is_open())
{
std::string delim = " ";
size_t pos = 0;
std::string token;
while (getline(fout, line))
{
Game newGame;
std::cout << line << std::endl;
}
while (getline(fout, line))
{
while ((pos = line.find(delim)) != std::string::npos)
{
token = line.substr(0, pos);
std::cout << token << std::endl;
line.erase(0, pos + delim.length());
}
std::cout << line << std::endl;
}
}
else
{
cout << "There was an error opening the file.";
}
cout << endl;
repeat:
cout << endl;
cout << "ADD | SHOW | DELETE | EDIT | SEARCH " << endl;
cout << "SAY : ";
cin >> option;
if(option == "ADD" || option == "Add" || option == "add")
{
serialNumber += 1;
Game NewGame;
NewGame.id = serialNumber;
cout << endl << "Name: ";
cin >> NewGame.title;
cout << "Year: ";
cin >> NewGame.year;
cout << "Developer: ";
cin >> NewGame.developer;
cout << "Publisher: ";
cin >> NewGame.publisher;
cout << endl;
Database.push_back(NewGame);
cout << endl;
cout << "Size is: " << Database.size();
fout << serialNumber << " " << Database[Database.size() - 1].title << " " << Database[Database.size() - 1].year << " "<< Database[Database.size() - 1].developer << " " << Database[Database.size() - 1].publisher << endl;
goto repeat;
}
if (option == "SHOW" || option == "Show" || option == "show")
{
ShowData(Database);
goto repeat;
}
if(option == "DELETE" || option == "Delete" || option == "delete")
{
int choose;
cout << "Delete Item No: ";
cin >> choose;
Database.erase(Database.begin() + (choose - 1));
cout << endl;
ShowData(Database);
goto repeat;
}
if(option == "SEARCH" || option == "Search" || option == "search")
{
cout << "Search By [ID, TITLE, YEAR, DEVELOPER, PUBLISHER] : ";
string choose;
cin >> choose;
if(choose == "ID" || choose == "Id" || choose == "id")
{
int idNumber;
cout << "ID No: ";
cin >> idNumber;
cout << endl;
cout << "ITEM NO" << "[" << idNumber << "]" <<endl;
cout << " TITLE: " << Database[idNumber - 1].title << endl;
cout << " YEAR: " << Database[idNumber - 1].year << endl;
cout << "DEVELOPER: " << Database[idNumber - 1].developer << endl;
cout << "PUBLISHER: " << Database[idNumber - 1].publisher << endl;
goto repeat;
}
else if (choose == "TITLE" || choose == "Title" || choose == "title")
{
string whatTitle;
cout << "Enter Title: ";
cin >> whatTitle;
for(size_t i = 0; i <= Database.size()-1; i++)
{
if(Database[i].title == whatTitle)
{
cout << endl;
cout << "ITEM NO" << "[" << i + 1 << "]" <<endl;
cout << " TITLE: " << Database[i].title << endl;
cout << " YEAR: " << Database[i].year << endl;
cout << "DEVELOPER: " << Database[i].developer << endl;
cout << "PUBLISHER: " << Database[i].publisher << endl;
}
}
goto repeat;
}
else if (choose == "YEAR" || choose == "Year" || choose == "year")
{
int whatYear;
cout << "Enter Year: ";
cin >> whatYear;
for(size_t i = 0; i <= Database.size()-1; i++)
{
if(Database[i].year == whatYear)
{
cout << endl;
cout << "ITEM NO" << "[" << i + 1 << "]" <<endl;
cout << " TITLE: " << Database[i].title << endl;
cout << " YEAR: " << Database[i].year << endl;
cout << "DEVELOPER: " << Database[i].developer << endl;
cout << "PUBLISHER: " << Database[i].publisher << endl;
}
}
goto repeat;
}
else if (choose == "DEVELOPER" || choose == "Developer" || choose == "developer")
{
string whatDeveloper;
cout << "Enter Developer Name: ";
cin >> whatDeveloper;
for(size_t i = 0; i <= Database.size()-1; i++)
{
if(Database[i].developer == whatDeveloper)
{
cout << endl;
cout << "ITEM NO" << "[" << i + 1 << "]" <<endl;
cout << " TITLE: " << Database[i].title << endl;
cout << " YEAR: " << Database[i].year << endl;
cout << "DEVELOPER: " << Database[i].developer << endl;
cout << "PUBLISHER: " << Database[i].publisher << endl;
}
}
goto repeat;
}
else if (choose == "PUBLISHER" || choose == "Publisher" || choose == "publisher")
{
string whatPublisher;
cout << "Enter Publisher Name: ";
cin >> whatPublisher;
for(size_t i = 0; i <= Database.size()-1; i++)
{
if(Database[i].publisher == whatPublisher)
{
cout << endl;
cout << "ITEM NO" << "[" << i + 1 << "]" <<endl;
cout << " TITLE: " << Database[i].title << endl;
cout << " YEAR: " << Database[i].year << endl;
cout << "DEVELOPER: " << Database[i].developer << endl;
cout << "PUBLISHER: " << Database[i].publisher << endl;
}
}
goto repeat;
}
}
if (option == "EDIT" || option == "Edit" || option == "edit")
{
int whichItem;
cout << "Enter Item No: ";
cin >> whichItem;
cout << endl << "Name: ";
string name;
cin >> name;
Database[whichItem - 1].title = name;
cout << "Year: ";
int year;
cin >> year;
Database[whichItem - 1].year = year;
cout << "Developer: ";
string developer;
cin >> developer;
Database[whichItem - 1].developer = developer;
cout << "Publisher: ";
string publisher;
cin >> publisher;
Database[whichItem - 1].publisher = publisher;
cout << endl;
ShowData(Database);
goto repeat;
}
fout.close();
system("PAUSE");
return 0;
}
答案 0 :(得分：0)
您可以创建一个如here所示的结构。
在示例中，它们具有一组结构。要访问struct的元素，请使用.运算符。
在C ++ 11中，您可以使用tuple而不是结构。
Tuple vs Struct - Stackoverflow
我们的想法是，第一个可以提供更多通用操作，而第二个可以提供更好的可读性，而且您不必记住数据成员的顺序，恕我直言。
[编辑]
AS R. Hasan表示，问题与this问题重复。
答案 1 :(得分：0)
我不确定你在寻找什么，但请考虑一下（并且不要忘记包含矢量）
首先，我们定义自定义结构
struct Game //your structure
{
int id;
std::string title;
int year;
std::string developer;
std::string publisher;
};
现在我们重载运算符＆gt;＆gt; （它类似于使用cin＆gt;＆gt; someVariable）。 Fstream已经有了编写标准类型变量的方法。
bool operator>>(std::fstream& fs, Game& g)
{
if (fs >> g.id >> g.title >> g.year >> g.developer >> g.publisher)
return true;
return false;
}
/*
fs >> g.id >> g.title equals (fs.operator>>(g.id)).operator>>(g.title) ...
*/
标准运算符＆gt;＆gt;返回对fstream的引用，因此我们只需一行代码即可编写所有内容。如果写入失败（例如，文件结束），我们返回false。
std::vector<Game> vec;
STL vector - 标准容器，包含您的游戏结构
if (fout.is_open())
{
for ( ; ; )
{
Game g; //creating instantiation of your struct Game
if (fout >> g) //reading from your file
vec.push_back(g); //1 of STL vector methods, check link to cppreference higher
else //if reading fails, we break our infinite loop
break;
}
}
for (auto x : vec) //going through every element of our vector.
cout << x.id << " "; //and printing first variable of your structure