ex12.29.cpp

/***************************************************************************
 *  @file       The code is for the exercises in C++ Primmer 5th Edition
 *  @author     Alan.W
 *  @date       28  DEC 2013
 *  @remark
 ***************************************************************************/

//!
//! Exercise 12.29:
//! We could have written the loop to manage the interaction with the user as a do
//! while (§ 5.4.4, p. 189) loop. Rewrite the loop to use a do while. Explain which
//! version you prefer and why.
//  Do while loop will execute the statement first and then checnk the condition.Thus
//  without specfic aim I prefer while.
//!

#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <set>

void toVector(std::ifstream &fin, std::vector<std::string> &v);

std::size_t
search(const std::string &kWord, const std::vector<std::string> &v,
            std::map<std::string, std::set<int>> &m);

void printLines(const std::string &kWord, const std::vector<std::string> &v,
                std::map<std::string, std::set<int>> &m);

int main()
{
    std::ifstream fin("test.txt");
    std::vector<std::string> v;

    //! store the file in the vector
    toVector(fin, v);

    do
    {
        //! codes for input
        std::cout << "enter:\n";
        std::string keyWord;
        std::cin >>keyWord;
        if(keyWord == "q")
        {
            std::cout << "\nBye!\n";
            break;
        }


        //! create the map to store the query result and get the count of occurrence
        std::map<std::string, std::set<int>> m;
        std::size_t count = search(keyWord, v, m);


        //! print the key word and count of occurrence.
        std::cout << "["
                     << keyWord
                        << "]:\n"
                          << count
                            <<" appears times in lines:\n";


        //! print lines in which the key word appears
        printLines(keyWord, v, m);
    }
    while(true);

    return 0;
}

//! store the file in the vector
void toVector(std::ifstream &fin, std::vector<std::string> &v)
{
    std::string line;
    while(std::getline(fin, line))  v.push_back(line);
}

//! store the query result in the map and return the amout of occurrence.
std::size_t
search(const std::string &kWord, const std::vector<std::string> &v,
            std::map<std::string, std::set<int>> &m)
{
    std::size_t count = 0;

    //! each line
    for(std::size_t index = 0; index != v.size(); ++index)
    {
        std::stringstream lineStream(v[index]);
        std::string word;

        //! each word
        while(lineStream >> word)
            if(word == kWord)
            {
                ++count;
                m[kWord].insert(index);
            }
    }

    return count;
}

//! print lines in which the key word appears
void printLines(const std::string &kWord, const std::vector<std::string> &v,
                std::map<std::string, std::set<int> > &m)
{
    //! fetch the set that stores the query result
    std::set<int>&  set = m[kWord];

    //! print each line in which the key word appears
    for(const auto &index : set)
    {
        std::cout << "( Line "
                    << index
                        <<" ) : "
                            << v[index]
                                <<"\n";
    }

}