map 字典翻译

#include<iostream>
#include<string>
#include<map>
#include<fstream>
#include<sstream>
using namespace std;
//map count word
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;
	map_file.open("trans.txt");
	if(!map_file)
		throw runtime_error("no transformation file");
	while(map_file>>key>>value)
		trans_map.insert(make_pair(key,value));
	ifstream input;
	input.open("input.txt");
	if(!input)
		throw runtime_error("on input file");

	string line;
	while(getline(input,line))
	{
		istringstream stream(line);
		string word;
		bool firstword = true;
		while(stream>>word)
		{
			map<string, string>::const_iterator map_it= trans_map.find(word);
			if(map_it != trans_map.end())
				word = map_it->second;
			if(firstword)
				firstword = false;
			else cout<< " ";
			cout<<word;
		}
		cout<<endl;
	}
	return 0;
}