[求助]这个程序的问题在哪？

#include<iostream>
#include<exception>
#include<stdexcept>
#include<fstream>
#include<sstream>
#include<string>
#include<map>

using namespace std;

ifstream& open_file(ifstream &in,const string &file)
{
in.close();
in.clear();
in.open(file.c_str());
return in;
}

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[1]))
throw runtime_error("no inputfile");
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;
}

/*abnormal program termination非正常程序终止*/