How Can I Return a 2D Array from a C Function?

Returning 2D Arrays in C Functions

In C , when working with arrays and functions, it's often necessary to return multidimensional arrays. This article addresses the specific question of how to return a 2D array from a function in C .

The provided code attempt, MakeGridOfCounts(), aims to return a 2D array but falls short due to array decay. Instead, to properly return a 2D array, a pointer to the array must be returned.

Creating 2D Arrays Dynamically

To overcome the limitations of static arrays, C offers a way to create multidimensional arrays dynamically. The following code demonstrates how to create a new 2D array on the heap:

int** create2DArray(unsigned height, unsigned width) {
  int** array2D = 0;
  array2D = new int*[height];

  for (int h = 0; h < height; h++) {
    array2D[h] = new int[width];

    for (int w = 0; w < width; w++) {
      // fill in some initial values
      array2D[h][w] = w + width * h;
    }
  }

  return array2D;
}

This function takes two parameters, height and width, and returns a pointer to a newly created 2D array of size [height x width].

Returning the Pointer

To return the dynamically created 2D array from a function, a pointer to the array is returned. This pointer points to the first element of the array and provides access to the entire array:

int** MakeGridOfCounts() {
  int** cGrid = create2DArray(6, 6);
  return cGrid;
}

Memory Cleanup

When working with dynamically allocated arrays, it's crucial to remember to clean up the memory after use. Otherwise, memory leaks can occur:

for (int h = 0; h < height; h++) {
  delete[] my2DArray[h];
}
delete[] my2DArray;
my2DArray = 0;

Conclusion

By following the techniques outlined above, you can effectively return 2D arrays from functions in C . Remember to create the array dynamically to avoid limitations with static arrays and clean up the allocated memory after use.

The above is the detailed content of How Can I Return a 2D Array from a C Function?. For more information, please follow other related articles on the PHP Chinese website!