Trying to initialize and fill a 2D char array with using structure

Question

What I am trying to do is use a structure to create and display a 2D array of characters in the function 'function1( )'. This array will be sent back to the main( ) so I can use it further in my program. However my program is plagued with problems. I am having trouble with pointers. I assume my problem is somewhere with either my pointers or my variables. I've tried several combinations with no effort. As a beginner, it probably is some odd combination that is not coming to my mind.

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

#define ROW 13
#define COL 16

typedef struct letter_array {
    char** letters;
    struct letter_array *ltr_ptr;
} larray;

void function1 (larray ** letter1[*][16]);
int function2 (larray letter2[][16]);
int function3 (larray letter3[][16]);
void function4 (int hor_ans, int ver_ans);

int main (void)
{
    larray letter_list;
    int vert, hori, **lptr;

    lptr = malloc(ROW*sizeof(int*));

    for(vert = 0; vert<ROW; vert++)
    {
        lptr [vert] = malloc(COL*sizeof(int));
    }


    printf("\n \t\t\t *** Hello! ***");


    printf("\n This program will create a random selection of 180 upper-case"
           " characters. \n\n");

    function1(&letter_list); //Problem #1


    printf("\n\nThank you for using my random character array program. \n"
           "\t\t Have a good day! \n");

    return ( 0 ) ;
}    


void function1 (larray **letter1 [][16])
{
    int i, z, funptr;

    srandom((unsigned)time(NULL));

    for(i=0; i<12; i++)
    {
        letter1 [i] <- (int*) funptr;     // Problem #2-3
        for(z=0; z<15; z++)            
        {
            letter1[i][z] = random( )%26+'A';  // Problem #4
            printf("%c ", letter1[i][z]);
        }
        printf("\n");
    }

    return ;
}

The errors are below and commented.

1. warning:passing argument 1 of 'function1' from incompatible pointer type
2. warning: cast to pointer from integer of different size
3. error: wrong type argument to unary minus
4. warning: assignment makes pointer from integer without a cast

Answer 1

I hope this helps.

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

#define ROW 13
#define COL 16

typedef struct letter_array {
    char** letters;
    struct letter_array *ltr_ptr;
} larray;

void function1 (larray * letter1);  // here you just need a pointer to the structure
int function2 (larray letter2[][16]);
int function3 (larray letter3[][16]);
void function4 (int hor_ans, int ver_ans);

int main (void)
{
    larray letter_list;
    int vert, hori;

    letter_list.letters = malloc(ROW*sizeof(int*)); // allocate memory to the char pointer in the structure

    for(vert = 0; vert<ROW; vert++)
    {
        letter_list.letters[vert] = malloc(COL*sizeof(int));  // allocate the second 2D
    }


    printf("\n \t\t\t *** Hello! ***");


    printf("\n This program will create a random selection of 180 upper-case"
       " characters. \n\n");

    function1(&letter_list); //Problem #1 pass a pointer to the structure


    printf("\n\nThank you for using my random character array program. \n"
       "\t\t Have a good day! \n");

    return ( 0 ) ;
}


void function1 (larray *letter1) // just needs a pointer to the structure
{
    int i, z;

    srandom((unsigned)time(NULL));

    for(i=0; i<ROW; i++)   // used ROW
    {
        //letter1->letters[i] <- (int*) funptr;     // Problem #2-3  this line not needed as near as i can tell
        for(z=0; z<COL; z++)  // used COL
        {
            letter1->letters[i][z] = random( )%26+'A';  // Problem #4 dereference pointer to member char **
            printf("%c ", letter1->letters[i][z]);
        }
        printf("\n");
    }

    return ;
}