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

void main()
{
    unsigned int x = -1;
    int y = ~0;
    if (x == y)
        printf("same\n"); // same
    else
        printf("not same\n");

    int a[][3] = {1,2,3,4,5,6};
    int (*ptr)[3] = a;
    /*
    int a[][3] is like:
    {{1,2,3},
     {4,5,6}};
    */
    printf("%d %d \n", (*ptr)[1], (*ptr)[2]); // 2 3
    ++ptr;
    printf("%d %d \n", (*ptr)[1], (*ptr)[2]); // 5 6
    ptr--;
}