Thread: ifstream problem

I'm trying to use files, but have an error.

Code:

#include <iostream>
#include <fstream>
using namespace std;

int main(int argc, char *argv[]) {
 if(argc != 3) {
  cout << "Usage: cpp <infile (.cpp)> <outfile (.html)>" << endl;
  return 1;
 }
 ifstream in(argv[1], (ios::in | ios::trunc));
 if(!in.is_open()) {
  cout << "Error opening '" << argv[1] << "'." << endl;
  return 1;
 }
 ofstream out(argv[2], ios::out);
 if(!out.is_open()) {
  cout << "Error opening '" << argv[2] << "'." << endl;
  return 1;
 }
 in.close();
 out.close();
}

I ran the program with the command line: "cpp one.cpp out.html" where one.cpp and out.html are files that are in the same directory, but I always get "Error opening 'out.cpp'." Anyone got any ideas? Thanks !

You're trying to open an input stream using an output only flag (trunc). You cannot write to an istream, therefore you cannot truncate it.

Duh - thanks, I must have been thinking backwards .