Finding Horizontal pairs in a C multidimensional array

Question

I have been struggling for a while with my program. I am trying to find horizontal pairs in an array that is setup in function1. My goal is to change the original array in another function. Then process that array to find a horizontal pair.

One problem that has occurred is when I run the program, the result is zero. Another problem is the gcc warning in function 1, warning: comparison between pointer and integer. The other problem is another gcc warning (marked by the **) warning: passing argument 1 of 'function1' from incompatible pointer type.

I appreciate any help, as a beginner, I have spent several hours on this problem and have tried to find solutions, but trying to use pointers and using struct and typedef have not worked. :(

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

void function1 (int letter1[][16]);
void function2 (int letter2[][16]);

int  main ( void )
{  

  int letter_array [13][16];

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

  **function1(&letter_array);**

  function2(letter_array);

return ( 0 ) ;
}    


void function1 (int letter1 [][16])
{
  int i, z; 
  srandom((unsigned)time(NULL));

  for(i=0; i<=11; i++)
    {
       for(z=0; z<=14; z++)
       {
          letter1 [i][z] = random( )%26+65;
          printf("%c ", letter1 [i][z]);
       }
       printf("\n");
    }

  return ;
  }

void function2 (int letter2 [][16])
  {
  int a,b; 
  int m=0;
    for( a = 0; a <= 11; a++)
    {
       for( b = 0 ; b <= 14; b++)
       {
            if (letter2 == (letter2 + 1))
            m++;
       }
    }
  printf("\nThe number of horizontal pairs of characters"
    " are: %d", m);

  return ;

Answer 1

Just remove the ampersand & from the argument.

Change

function1(&letter_array);

to

function1(letter_array);

EDIT: Also change

if (letter2 == (letter2 + 1))

to

if (letter2[a][b] == (letter2[a][b+1]))

Answer 2

The warning is occurring because you are passing a pointer to an array[][16] into function1 instead of the array itself. This can be resolved by removing the &:

function1(letter_array);

The program is returning 0 because of the return statement at the end of your main function.