preventing an accidential overwrite

//-std=c99 -Wall -Wextra -Wpedantic -Wshadow

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

int main()
{

    FILE *fp;
    char fileName[] = "test_text_file.txt";

    fp = fopen(fileName, "r");

    if (fp)
    {
        printf("WARNING: file \"%s\" already exists ! Overwrite it ? [Y/N]\n", fileName);

        char c = toupper(getchar());

        if ( c != 'Y' )
        {
            printf("Not overwriting. Bye !\n");
            fclose(fp);
            return 0;
        }

        fclose(fp);

    }

    fp = fopen(fileName, "w");

    if (!fp)
    {
        printf("ERROR: can't open file \"%s\" for writing !\n", fileName);
        return -1;
    }

    fprintf(fp,"%s\n", "some text");

    fclose(fp);

    printf("INFO: a \"%s\" file has been written (overwritten). Bye !\n", fileName);

    return 0;
}