Thread: 2D matrix pointers regarding functions

Hey this is my code, i want to seperate matrix printing and intialisation into functions as shown (and get then out of main)
however I can't get it to work. I am able to pass 1D arrays but i can't work out 2D matrices

Code:

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

#define MAX_CUSTOMERS 100
#define MAX_PRODUCTS 100

void printMatrix( int matrix[][], int rows, int cols )
{ int n, m;
  /* Print matrix to check it worked */
  for( n=0; n<rows; n++ )
     { printf( "\n" );
       for ( m=0; m<cols; m++ )
        { printf(" %d", matrix[n][m] ); }
     }
     printf( "\n" );
  return;
}

void initialiseMatrix( int matrix[][] )
{  int n, m;
   /* Set all values to -1 to indicate NOT valid */
   for( n=0; n<100; n++ )
    { for ( m=0; m<100; m++ )
       { matrix[n][m]=0; }
    }
   return;
}

int main()
{
   int matrix[MAX_CUSTOMERS][MAX_PRODUCTS];
   initialiseMatrix( matrix );
   printMatrix( matrix, 100, 100 );
   return 1;
}

Thanks