c++学习笔记第八章（IO操作）

一、IO标准库类型和头文件
头文件：
iostream，读写流，如cout cin。
fstream：读写文件，ifstream：从文件中读取，ofstream，写到文件中去。

二、IO对象不可复制或赋值。

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <cstring>

using namespace std;

vector<string> names;
vector<string> phones;

void process(string);

int main()
{
    vector<string> files;
    string fileName, s;

    cout << "Enter [i] enames: (Ctrl + Z to end)" << endl;

    while (cin >> fileName && strcmp(fileName.c_str(),"stop"))
    {
        files.push_back(fileName);
    }
    ifstream input;
    ofstream file2;
    file2.open("result");

    vector<string>::const_iterator it = files.begin();

    while (it != files.end())
    {
        input.open(it->c_str());
        if (!input)
        {
            cerr << "error can not open the file " << *it << endl;
            input.clear(); //清除文件流的状态
            ++it;
        }
        else
        {
            while (input >> s)
            {
                process(s);
            }
            input.close();
            input.clear();
            ++it;

        }
    }

    cout << "complete " << "will output all names and phones " << endl;
    int name_nus = 0;
    int phone_nus = 0;
    vector<string>::const_iterator phone = phones.begin();
    vector<string>::const_iterator name = names.begin();

    while (name != names.end() && phone != phones.end())
    {
        cout << "names=" << *name << "phones=" << *phone << endl;

        if (file2.good())
            file2 << *name << "," << *phone << endl;

        name++;
        name_nus++;
        phone++;
        phone_nus++;

    }
    if (file2)
    {
        file2.close();
    }

    cout << "finaly phones nus = " << phone_nus << "names nums = " << name_nus << endl;

    return 0;

}

void process(string s)
{
    string::size_type position;
    position = s.find("FN:");
     if (position != s.npos)  //如果没找到，返回一个特别的标志c++中用npos表示
     {
         position = s.find(":");
        position++;
          cout << "position is : " << position << "name=" << s.substr(position) << endl;
        names.push_back(s.substr(position));
     }
    else
     {   //find phone number
        position = s.find("CELL:");
        if (position != s.npos)
        {
            position = s.find(":");
            position++;
              cout << "position is : " << position << "phone=" << s.substr(position) << endl;
            phones.push_back(s.substr(position));
        }
        else
        {
              cout << "Not found" << endl;
        }
    }
}