#include <stdio.h>
#include <stdio.h>
#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>



    void replace( std::string& str,
                  	const std::string& from, 
                        const std::string& to )
    {
      using std::string;
      string::size_type pos = str.find( from );
      while ( pos != string::npos )
      {
        str.replace( pos, from.size(), to );
        pos = str.find( from, pos+from.size()-1 );
      } 
    }




//==========================================================================
int main(int argc, char **argv)
{
  
  if (argc!=4) 
    {
      std::cerr << "usage : "<< argv[0] <<" fileIn  \"FindString\" \"ReplaceString\"" << std::endl;
      return 1;
    }

  FILE *ffIn;
  std::string fileIn;
  std::string fileOut;
  std::string findstring;
  std::string replacestring;
  std::string lineStr;
  char strTmp[255];

  fileIn 	= argv[1];
  findstring 	= argv[2];
  replacestring = argv[3];

  ffIn =  fopen(fileIn.c_str(),"r");
  if (ffIn){
        while(!feof(ffIn)){
	    fgets( strTmp , 255, ffIn );
            lineStr=strTmp;
	    if( feof(ffIn) && (lineStr.length()==1) ) { 
	    } else {
	      replace( lineStr,findstring, replacestring );
	      std::cout << lineStr;
            }
        }
	fclose(ffIn);	
  } else {
      std::cerr << "ERROR. File : "<< argv[1] <<" Not exists." << std::endl;
      return 1;
  }


  return 0;
}
//==========================================================================