Read from file (ifstream) and write to file (ofstream) - problems with encoding - c++

Question

Note: I'm rather a c++ rookie.
I've the following problem:
I read from a file and want to replace string parts with other string parts. Simple task, should be easy to do. I did some experiments with setmode, but without success. I googled also imbue, but it didn't help me either.
There might be minor code issues, but please focus on the problem. The test data for conversion is given below:
int main(int argc, char** argv) {
stringstream strs;
//Choose output file
ofstream ofile;
string filename;
cout << "Ausgabepfad eingeben" << endl;
cin >> filename;
ofile.open(&filename[0]);
//Choose input file
ifstream ifile;
cout << "Quellpfad eingeben" << endl;
cin >> filename;
ifile.open(&filename[0]);
//Choose decoding - doesnt work, I know - That was for experiments
int mode = 0;
cout << "Decoding wählen\n1 für _O_TEXT\n2 für _O_BINARY\n3 für _O_U16TEXT\n4 für _O_U8TEXT\n5 für _O_WTEXT" << endl;
cin >> mode;
/* switch(mode){
case 1:
_setmode (_fileno(ifstream), _O_TEXT);
break;
case 2:
_setmode (_fileno(ifstream), _O_BINARY);
break;
case 3:
_setmode (_fileno(ifstream), _O_U16TEXT);
break;
case 4:
_setmode (_fileno(ifstream), _O_U8TEXT);
break;
case 5:
_setmode (_fileno(ifstream), _O_WTEXT);
break;
default:
cerr << "ungültige Codierung gewählt"
}
*/
//Choose search string and replacement string
ifile.seekg(0); //not necessary, I know
string searchstr = "";
cout << "Suchstring eingeben" << endl;
cin >> searchstr;
string fillstr;
cout << "Ersetzungsstring eingeben" << endl;
cin >> fillstr;
cout << fillstr;
int marker = 0;
if(searchstr.length()<1){
return 0;
}
//actual program
while(!ifile.eof()){
int counter = 0;
ifile.seekg(marker);
char current = ifile.get();
if(current==searchstr[0]){ //if the first search letter matches, seet, if the others do.
marker++;
counter++;
for(int i = 1; i < searchstr.length(); i++){
ifile.seekg(marker);
if(ifile.get()==searchstr[i]){
counter++;
marker++;
}else{
marker-i;
break;
}
}
if(counter == searchstr.length()){
ofile << fillstr;
cout << endl;
}
}else{
ofile << ifile.get();
cout << ifile.get();
}
marker++;
}
ifile.close();
ofile.close();
cout << endl;
return 1;
}
The following string
|-
should be replaced by
\n
The text (sample) is:
|[[Allgemeines Deutsches Kommersbuch:1|1]]
|1
|[[Abend wird's, des Tages (Körner)]]
|[[Die Eichen (Körner)]]
|-
|[[Allgemeines Deutsches Kommersbuch:2|2]]
|2
The program runs, but it doesn't work. The output is lots of numbers without any sense.

Answer 1

The output is lots of numbers without any sense.
The call ifile.get() returns a value of type int_type. Thus << outputs all these integer values.
Replace
ofile << ifile.get();
(doing formatted output of integers) with
ofile << char( ifile.get() );
or (preferred, using unformatted input and output)
ofile.put( ifile.get() );

Answer 2

It's almost always a better idea to express the problem in terms of standard streams, iterators and algorithms:
#include <iostream>
#include <string>
#include <sstream>
#include <algorithm>
// lets get the logic right in terms of streams
void replace_all(std::ostream& dest, std::istream& source,
const std::string& search_for, const std::string& replace_with)
{
std::string line;
while (std::getline(source, line)) {
auto ipos = line.begin();
while (ipos != line.end())
{
ipos = std::search(ipos, line.end(), search_for.begin(),
search_for.end());
if (ipos != line.end())
{
auto start_index = std::distance(line.begin(), ipos);
line.replace(ipos, std::next(ipos, search_for.length()),
replace_with);
ipos = std::next(line.begin() + start_index + replace_with.length());
}
}
dest.write(line.data(), line.size());
dest.put('\n');
}
}
// now test
int main()
{
std::string search_for = "|-";
std::string replace_with = "";
std::istringstream source_stream("|[[Allgemeines Deutsches Kommersbuch:1|1]]\n"
"|1\n"
"|[[Abend wird's, des Tages (Körner)]]\n"
"|[[Die Eichen (Körner)]]\n"
"|-\n"
"|[[Allgemeines Deutsches Kommersbuch:2|2]]\n"
"|2\n");
std::ostringstream dest_stream;
replace_all(dest_stream, source_stream, search_for, replace_with);
std::cout << dest_stream.str();
return 0;
}
// todo: write a new main which asks for filenames, builds ifstreams and ofstreams, and calls replace_all()
expected output:
|[[Allgemeines Deutsches Kommersbuch:2|2]]
|2
Jewels-MacBook-Pro:play richardh$ ./replace.cpp
|[[Allgemeines Deutsches Kommersbuch:1|1]]
|1
|[[Abend wird's, des Tages (Körner)]]
|[[Die Eichen (Körner)]]
|[[Allgemeines Deutsches Kommersbuch:2|2]]
|2