Multiple Dimension Array
#include <stdio.h>
int main()
    int a[3][4] = {{1,2,3,4},{9,10,11,12},{13,14,15,16}};
    printf("%d\n", a[0][0]);
    printf("%d\n", a[2][3]);
    printf("%d\n", *(*(a+2)+3));
    printf("%d\n", *(*a + 2*4 + 3));    // a is pointer to pointer



  • for int a[m][n], we can use *(*(a+x) + y) and *(*a + x*n + y) to access a[x][y]. In both methods, we need to dereference twice.
  • If we pass the array a[][] to a function as parameter, it will be like we passing in the pointer to pointer a. However we need to denote the n, because therefore compiler know how to translate it when we write a[x][y].
char *color_display_buffer = (char*) 0xB8000;
color_display_buffer[2*(80*row+col)] = 'A';

can be changed to
typedef char                 ONE_CELL[2];
typedef ONE_CELL        ONE_ROW[80];
ONE_ROW *color_display_buffer = (ONE_ROW*) 0xB8000
color_display_biffer[row][col][0] = 'A';
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