How to reverse the order of a input file using C++?

Question

I need to reverse the order of the file and outputted into another file. For example, the

input:

hello
this is a testing file again
just    so    much  fun

Expected output:

just    so    much  fun
this is a testing file again 
hello

This is my current code, it printed to where it reverses the order of the lines but also the order of the characters of each word.

Current:

nuf  hcum    os    tsuj
 niaga elif gnitset a si siht
olleh

int print_rev(string filename, char c){
  ifstream inStream (filename);
  ofstream outStream;
  inStream.seekg(0,inStream.end);
  int size = inStream.tellg();
  outStream.open("output.txt");

  for (int j=1; j<=size; j++){ 
    inStream.seekg(-j, ios::end);
    c=inStream.get();
    outStream << c;
  }

  inStream.close();
  outStream.close();
  return 0;
}

Answer 1

You're reversing the whole file, character by character. What you want to do is read in each line separately, and then reverse the line order.

A stack of lines seems like a good choice for this :

int printRev(string filename)
{
    stack<string> lines;
    ifstream in(filename);
    string line;
    while (getline(in, line))
    {
        lines.push(line);
    }
    ofstream out("output.txt");
    while (!lines.empty())
    {
        out << lines.top() << endl;
        lines.pop();
    }
    return 0;
}