c array question

true_atlantis · 03-27-2006, 06:28 PM

why do i get an error in this code? i get an incompatible types on line

words[num_words]=string;

what am i doing wrong? what is incompatible? or how can i fix it?

Code:

#include <stdio.h>

const int max_word_length=50;

int main(){
  FILE *file;
  file=fopen("words", "r");

  char words[1000][max_word_length];

  char string[max_word_length];
  int num_words=0;

  while(fgets(string,sizeof(string),file) != NULL){
    words[num_words]=string;
    num_words++;
  }
}

frob23 · 03-27-2006, 08:24 PM

You need to use strcpy(). Right now you're attempting to copy the address of the string not the contents. The other way would be to make it an array of char pointers... but you would then need to dynamically allocate memory (and deallocate it when finished).

true_atlantis · 03-27-2006, 09:11 PM

wow... im an idiot... thats what happens when coding for multiple hours in a row

firstfire · 03-27-2006, 11:49 PM

You forget about c-array alignment (row-major) -- swap dimentions:

char words[max_word_length][1000];

Then words[k] -- is the k-th word in the list.
And (of course) you need to use strcpy.

addy86 · 03-28-2006, 02:37 AM

Quote:

Originally Posted by firstfire

You forget about c-array alignment (row-major) -- swap dimentions:

char words[max_word_length][1000];

Why?
char words[1000][max_word_length];
defines an array of 1000 strings with a length of max_word_length each, and I think, that's what true_atlantis wants.

By the way, your loop-head should rather look something like this:
while(fgets(string,sizeof(string),file) != NULL && num_words < 1000)