11、C++Primer 4 thノート、関連容器(1)

word_count.insert(map<string, int>::value_type("Annna", 1));

//the following is equivalent to the above

word_count.insert(make_pair("Anna", 1));

pair<map<string, int>::iterator, bool> ret =  word_count.insert(make_pair(word, 1));

#include "map"

#include "string"

#include "fstream"

#include "iostream"

#include "sstream"

using namespace std;



// opens in binding it to the given file

ifstream& open_file(ifstream &in, const string &file)

{

	in.close(); // close in case it was already open

	in.clear(); // clear any existing errors

	// if the open fails, the stream will be in an invalid state

	in.open(file.c_str()); // open the file we were given

	return in; // condition state is good if open succeeded

}



int main(int argc, char **argv)

{

	map<string, string> trans_map;

    string key, value;

	if (argc != 3)

		throw runtime_error("Wrong number of arguments");

	ifstream map_file;

	if (!open_file(map_file, argv[1]))

		throw runtime_error("No transformation file");

	while (map_file >> key >>value)

	{

		trans_map.insert(make_pair(key, value));

	}



	ifstream input;

	if (!open_file(input, argv[2]))

	{

		throw runtime_error("No input file");

	}

	string line;

	while (getline(input, line))

	{

		istringstream mystream(line);

		string word;

		bool firstword = true;

		while (mystream >> word)

		{

			map<string, string>::iterator map_it = trans_map.find(word);

			if (trans_map.end() != map_it)

				word = map_it->second;

			if (firstword)

				firstword = false;

			else

				cout << " ";

			cout << word;

		}

		cout << endl;

	}

	return 0;

}