CareerCup

int * arr = (int * ) malloc(sizeof(int)*nrows*ncols);

int **dd;
int i;
int row,col;

scanf("%d",&row);
scanf("%d",&col);

dd = malloc(sizeof(int*) * row);

for(i=0;i<row;i++)
dd[i] = malloc(sizeof(int)*col);

Got the code from some forum.

int main()
{
  int i; /* general purpose variable used for loop index */
  int j; /* general purpose variable used for loop index */


  int **a;     /* this is the array name */
  int size_x; /* this variable will be used for the first  dimension */
  int size_y; /* this variable will be used for the second dimension */


  /* suppose we want an array of int: a[5][3] */
  size_x = 5;
  size_y = 3;

  /*  allocate storage for an array of pointers */

  a = malloc(size_x * sizeof(int *));

  /* for each pointer, allocate storage for an array of ints */
  for (i = 0; i < size_x; i++) {

    a[i] = malloc(size_y * sizeof(int));
  }

  /* just for kicks, show the addresses (note: not all sequential) */
  /* assign an arbitrary value to each element        */

  for (i = 0; i < size_x; i++) {
    for (j = 0; j < size_y; j++) {
      printf("&a[%d][%d] = %p\n", i, j, &a[i][j]); /* show the addresses */

      a[i][j] = i * size_y + j; /* just some unique number for each element */
    }
    printf ("\n");
  }

  /* now show the contents that were assigned */

  for (i = 0; i < size_x; i++) {
    for (j = 0; j < size_y; j++) {
      printf("a[%d][%d] = %2d\n", i, j, a[i][j]);

    }
    printf ("\n");
  }

  /* now for each pointer, free its array of ints */
  for (i = 0; i < size_y; i++) {

    free(a[i]);
  }
  /* now free the array of pointers */
  free(a);

  return 0;
}

int (*a)[columns] = malloc(sizeof(a) * rows);

int **a;
get row1 and col1
// allocate required space for given dimension
space1 = (int*) malloc(sizeof(int)*row1*col1);

// allocate row pointers
a = (int**) malloc(sizeof(int*)* row1);

// break regions and assign the row pointers
for(i=0; i<row1; i++)
a[i] = space1 +(i*col1);

//Advantage reduced number of mallocs

template<class T>
bool make2DArray(T**& x, int rows, int cols) {
  try{
  x = new T*[rows]; // S* x = new S[rows], with S = T*;
  for (int i=0; i<rows; i++)
    x[i] = new T[cols];
  return true;}
  catch (xallox) {return false;}
}

bool delete2DArray(T**& x, int rows) {
  for (int i=0; i<rows; i++)
    delete [] x[i];
  delete [] x; // confirm this
  x = 0; // x is just the null pointer
}

int row, col;
	int **ARR;
	row = 3;
	col = 4;

	ARR = (int **)malloc(row * sizeof(int*));
	for(int i = 0; i<row; i++)
	{
		ARR[i] = (int*)malloc(col * sizeof(int));
	}