Create file using fstream if it doesn't exist that utilizes seekp/seekg?

Question

fstream file(file_1.c_str(), ios::out | ios::in | ios::ate); //convert string to const char*

Error if File does not exist. if ( ! file ) = true

fstream file(file_1.c_str(), ios::out | ios::in | ios::app); //convert string to const char*

using ios::app seekg & seekp functions not working. file.seekg(4, ios_base::beg);

I would like to have:

1. USER input file name
2. create file if NON existing
3. use seekg & seekp;
4. Not remove the file if you run the program again.

Answer 1

If I understand you correctly, you need something like this:

#include <iostream>
#include <fstream>
#include <string>

int main()
{
    string name;
    std::cin>>name;
    std::ofstream file (name.c_str());
    outfile << "Text in file." << std::endl;
    file.close();
    return 0;
}