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

int main ()
{
  double A[10][10];     // Static allocation of space to array A.
  double **B;           // We'll use malloc to assign space to B.
  int i;

  printf ("BEFORE malloc: Address A=%p  Address B=%p\n", A, B);
  // Prints an address for A, but zero for B

  // Assign space for first dimention of B (an array of pointers-to-double)
  B = (double**) malloc (10 * sizeof(double*));
  for (i=0; i<10; i++) {
    B[i] = (double*) malloc (sizeof(double));
  }
  
  printf ("AFTER malloc: Address A=%p  Address B=%p\n", A, B);
  // Prints an address for A and newly allocated address for B.

  // Two ways of assigning values:
  A[3][4] = 5.55;
  *((double*)A + 5*10 + 6) = 6.66;
  printf ("A[3][4]=%lf  A[5][6]=%lf\n", A[3][4], A[5][6]);    // Prints 5.55 and 6.66.

  // Twy ways of assigning values:
  B[3][4] = 7.77;
  *((*(B + 5)) + 6) = 8.88;
  printf ("B[3][4]=%lf  B[5][6]=%lf\n", B[3][4], B[5][6]);    // Prints 7.77 and 8.88

  // Free the individual small arrays:
  for (i=0; i<10; i++) {
    free (B[i]);
  }
  // Free the array of double-pointers:
  free (B);
}