Question

I have a function that takes in a filename (string) and I want to have an array of filenames (strings) to check to see if the filename taht was passed in is in the array and if not add it to it. Here is what I got so far.

bool read_file(char * filename, bool warnings){
  //Check to see if filename is in array files
  static char * files[MAXFILES];
  static int counter = 0;
  for(int i=0;i<counter;i++){
    if(strcmp(filename,files[i]) == 0){
      fprintf(stdout, "Error\n");
      return 0;
    }
    else{
      files[counter]=filename;
      counter++;
    }
  }
  FILE * fp = fopen(filename,"r");
  if(fp == NULL){
    if(warnings){
      fprintf(stderr, "Can't open the file %s\n",filename);
      return 0;
    }
    else{
      return 0;
    }
  }
  else{
    fclose(fp);
    fp = NULL;
    return 1;
  }
}

For some reason it wont add filenames to files[] any help would be appricated.

Answer 1

Take a look at the first time through your loop (when i == 0 and counter == 0):

static int counter = 0;
for(int i = 0; i < counter; i++) {
    // this never runs
}

i < counter is always false, because counter is incremented in the body of the for loop.

You’ll need to rethink your logic. This function is doing a lot of stuff. Maybe something like this infront of the loop will help:

if (counter == 0) {
    // first time in the function, just add the filename
    files[counter]=filename;
    counter++;
}
else {
    for (int i = 0; i < counter; i++) {
        ...
    }
}

However, you might have better luck splitting this into a couple functions. One to add a filename to the array, another to check if it’s already there, a third to open the file, etc.