I have this code example, but I don't understand why changing the values in the array inside outputUsingArray() are changing the original array.

I would have expected changing the values of the array in outputUsingArray() would only be for a local copy of the array.

Why isn't that so?

However, this is the behaviour I would like, but I don't understand why it work.

#include <stdlib.h>
#include <stdio.h>
void outputUsingArray(int array[][4], int n_rows, int n_cols) {
  int i, j;

  printf("Output Using array\n");
  for (i = 0; i < n_rows; i++) {
    for (j = 0; j < n_cols; j++) {
      // Either can be used.
      //printf("%2d ", array[i][j] );
      printf("%2d ", *(*(array+i)+j));
    }
    printf("\n");
  }
  printf("\n");

  array[0][0] = 100;
  array[2][3] = 200;

}

void outputUsingPointer(int (*array)[4], int n_rows, int n_cols) {
  int i, j;

  printf("Output Using Pointer to Array i.e. int (*array)[4]\n");
  for (i = 0; i < n_rows; i++) {
    for (j = 0; j < n_cols; j++) {
      printf("%2d ", *(*(array+i) + j ));
    }
    printf("\n");
  }
  printf("\n");
}

int main() {

  int array[3][4] = { { 0, 1, 2, 3 },
              { 4, 5, 6, 7 },
              { 8, 9, 10, 11 } };

  outputUsingPointer((int (*)[4])array, 3, 4);

  outputUsingArray(array, 3, 4);

  printf("0,0: %i\n", array[0][0]);
  printf("2,3: %i\n", array[2][3]);

  return 0;
}