Thread: Dynamic Memory Allocation Question

I have to set up an array of strings dynamically that I will read words in from a dictionary file (dictionary.txt). I know that the maximum length of letters for any given word is 19 letters. Also, maxWord will be given the value of the total number of words in the dictionary.txt file that I will be reading into memory.

Code:

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

char **dictionary;
const MAX_LENGTH = 19;
int maxWord;
int i;

FILE *ifp = fopen("dictionary.txt", "r"); // open dictionary file

fscanf (ifp, "%d", &maxWord);  // read number of words in dictionary

dictionary = malloc(maxWord * sizeof(char*));  // allocate memory

for (i = 0; i < maxWord; i++)

    dictionary[i] = malloc((MAX_LENGTH) * sizeof(char));

for (i = 0; i < maxWord; i++)  // read dictionary words into dictionary array

    {

    fscanf (ifp, "%s", dictionary[i]); 
    printf ("%s\n", dictionary[i]);  // temp. confirms dictionary array working

    }

fclose(ifp); // close dictionary.txt

}

My program compiles, and I confirmed with the printf statements that the array is working, but I get a program error when I get to a function that I send the dictionary array to. I send it in the following format.

Code:

myFunction (dictionary, otherVar, otherVar2);



void myFunction (char **dict[][MAX_LENGTH], int var, int var2) {

blah blah blah

}

I posted what a thought was important for brevity's sake. Here is the full code so far:

Code:

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

const MAX_LENGTH = 19;
int maxDictWords;
char **dictionary;

//
void readDictionary (int *wordCount) {
//

int i;
int maxWord;


FILE *ifp = fopen("dictionary.txt", "r"); // open dict file

fscanf (ifp, "%d", &maxWord); // read number of words in dictionary

dictionary = malloc(maxWord * sizeof(char*));

for (i = 0; i < maxWord; i++)

    dictionary[i] = malloc((MAX_LENGTH) * sizeof(char));

for (i = 0; i < maxWord; i++) // load dictionary array with words

    {

    fscanf (ifp, "%s", dictionary[i]); // input words into dictionary array
    //printf ("%s\n", dictionary[i]);

    }

fclose(ifp); // close dictionary.txt

}


//
void testingDictionary (char dict[][MAX_LENGTH], int max) {
//


//testing dict

int i;

for (i = 0; i < max; i++)

    printf ("%s\n", dict[i]);


}


// MAIN
int main(void) {
//

readDictionary(&maxDictWords);  // Read dictionary.txt into memory

testingDictionary(*dictionary, maxDictWords);

return 0;

}

Presently, the code prints the whole dictionary, but also a ton of erroneous data beyond the boundaries of the array.

How should I send dictionary to the testingDictionary function so that it only prints what is in the dictionary array?

I'm confused - you're using "maxDictWords" to determine how many words to print - but you're not giving it any values. It's declared, and passed to "readDictionary()", but "readDictionary()" stores that information in the local variable "maxWord". "maxDictWords" isn't even initialized!

Why are you declaring those variables globally? You're passing them to the functions correctly, so why not just declare them in main?

And I see some memory being allocated, but none of it being freed.

There's a few other things I see, but let's start there.

[edit] Dang! Too slow again!

Excellent. Thanks very much.