Question

I’m doing some C++ tutorials, and so far I am pretty damn good at it. However, there is one thing that perplexed and forced off the rail my knowledge acquiring, which gives me a headache.

How to create a file with its name given on the command line?

Answer 1

You’re asking about how to get a string from the command line to name the file to open?

#include <iostream>
#include <cstdlib>
#include <fstream>

int main(int argc,char *argv[]) {
    if(2>argc) {
        std::cout << "you must enter a filename to write to\n";
        return EXIT_FAILURE;
    }
    std::ofstream fout(argv[1]); // open a file for output
    if(!fout) {
        std::cout << "error opening file \"" << argv[1] << "\"\n";
        return EXIT_FAILURE;
    }
    fout << "Hello, World!\n";
    if(!fout.good()) {
        std::cout << "error writing to the file\n";
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}