2d array of strings declaration in C

Question

How to allocate a 2-d array of strings............By that I mean if t[][] is the array {char t[0][0]} should store a string, { char t[0][1] } should store a string etc........Can we use {char ***t } to accomplish this ..If so how should I approach it?? Or can we also go about doing it like { char **t[10] } , where 10 is the maximum length of any string I am going to enter in the array...

Answer 1

Edit:

To do this you will have to specify the cardinal of the second dimension and the maximum lenght of the string. Then use the name of the array with sizeof and the number of strings you want to allocat for:

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

int main(void) {

        /*  10 is the lenght of each string and 1 for the '\0'
            10 is the number of strings per each 2D array
            5 is the number of 2D arrays */
    char (*array)[10][10+1] = malloc(5*sizeof(*array));

    // Exemple
    strcpy(array[0][0], "hello, world");
    printf("%s\n", array[0][0]);
    return 0;
}

Live Demo

Answer 2

well first of all you said: By that I mean if t[][] is the array {char t[0][0]} should store a string, { char t[0][1] } , if t[0][1] would store a string then it's not a 2D array you want but rather a 3D array , in a 2D array it's t[0] that stores the string (because a string is an array , and 2D arrays are arrays of arrays) , having said that I'm going to show you how to Dynamically allocate memory for a 2D array and you can use the principle to create a 3D one.

char **matrix = NULL;
int i ;

matrix = malloc(sizeof(char) * ROWS);

for(i = 0 ; i < COLUMNS ; i++)
      matrix[i] = malloc(sizeof(char));

and there you have it , just don't forget to use free after you're done with that array

Edit :

to free a dynamically allocated 2D array you need to free the last thing you malloced first , like this :

for(i = 0 ; i < COLUMNS ; i++)
     free(matrix[i]);

 free(matrix);

Answer 3

You have to allocate an array of pointers to pointers to char, which is:

char ***array = (char ***)malloc(sizeof(char**)*ARRAY_X);

Then, you have to allocate each single array of pointers to chars:

for(int i = 0; i < ARRAY_X; i++){
    array[i] = (char **) malloc(sizeof(char *)*ARRAY_Y);
}

Finally you have to allocate strings:

for(int i = 0; i < ARRAY_X; i++){
    for(int j = 0; j < ARRAY_Y; j++){
        array[i][j] = (char *) malloc(sizeof(char)*ARRAY_Z);
    }
}

ARRAY_X and ARRAY_Y and ARRAY_Z are int indicating the dimension of the 2-d array of strings (which is a 3-d array of chars).