# Pastebin nZQNcepJ
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>

int
main()
{
    FILE *fp = fopen("./file.txt", "r");
    if (!fp)
    {
        switch (errno)
        {
            case ENOENT:
            {
                perror("File not found");
                fp = fopen("./file.txt", "w");
                if (!fp)
                {
                    perror("Failed to create file");
                    return EXIT_FAILURE;
                }
                /* write default file contents here */
                break;
            }
            default:
                perror("Failed to open file");
                return EXIT_FAILURE;
        }
    
    }
    /* read existing config here */

    return EXIT_SUCCESS;
}