Messages Order

内容：

说明：

按顺序打印输入信息

示例代码：

// MessagesOrder.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>

using namespace std;

class Message
{
public:
    Message() {}
    const string& get_text()
    {
        return msg_text;
    }

    bool operator < ( Message &m )
    {
        if( index < m.index )
        {
            return true;
        }

        return false;
    }
public:
    string msg_text;
    int index;
};

class MessageFactory
{
public:
    MessageFactory() {}
    Message create_message( const string& text )
    {
        num++;
        Message ma;
        ma.index = num;
        ma.msg_text = text;
        return ma;
    }
    static int num;
};

int MessageFactory::num = 0;

class Recipient
{
public:
    Recipient() {}
    void receive( const Message& msg )
    {
        messages_.push_back( msg );
    }
    void print_messages()
    {
        fix_order();

        for( auto& msg : messages_ )
        {
            cout << msg.get_text() << endl;
        }

        messages_.clear();
    }
private:
    void fix_order()
    {
        sort( messages_.begin(), messages_.end() );
    }
    vector<Message> messages_;
};

class Network
{
public:
    static void send_messages( vector<Message> messages, Recipient& recipient )
    {
        // simulates the unpredictable network, where sent messages might arrive in unspecified order
        random_shuffle( messages.begin(), messages.end() );

        for( auto msg : messages )
        {
            recipient.receive( msg );
        }
    }
};


//by zhaocl
int main()
{
    MessageFactory message_factory;
    Recipient recipient;
    vector<Message> messages;
    string text;

    while( getline( cin, text ) )
    {
        messages.push_back( message_factory.create_message( text ) );
    }

    Network::send_messages( messages, recipient );
    recipient.print_messages();

    system( "pause" );
    return 0;
}

知识点：

按序输出要重载操作符：<