Main.cpp

#include<iostream>
#include<fstream>
#include<string>
#include<map>
#include<sstream>
void word_transform(std::ifstream& map_file, std::ifstream& input)
{
	auto trans_map = buildMap(map_file);
	std::string text;
	while (getline(input, text)) {
		std::istringstream stream(text);
		std::string word;
		bool firstword = true;
		while (stream >> word){
			if (firstword)
				firstword = false;
			else
				std::cout << " ";
			std::cout << transform(word, trans_map);
		}
		std::cout << std::endl;
	}
}

std::map<std::string, std::string> buildMap(std::ifstream& map_file)
{
	std::map<std::string, std::string> trans_map;
	std::string key;
	std::string value;

	while (map_file >> key && getline(map_file, value))
		if (value.size() > 1)
			trans_map[key] = value.substr(1);
		else
			throw std::runtime_error("no rule for " + key);
	return trans_map;
}

const std::string &
transform(const std::string& s, const std::map<std::string,std::string> &m)
{
	auto map_it = m.find(s);
	if (map_it != m.cend())
		return map_it->second;
	else
		return s;
}

int main()
{

}