/**
 * Array in C
 * array_demo.c
 */
#include <stdio.h>
#include <stdlib.h>
int main () {
    // array on the stack
    int i;
    int a[5];
    for (i = 0; i < 5; i++) {
        a[i] = i * 10; 
    }
    for (i = 0; i < 5; i++) {
        printf("%d at %p\n", a[i], &(a[i]) );
    }
    
    // array on the heap
    int *b;
    b = malloc(5 * sizeof(int));
    for (i = 0; i < 5; i++) {
        *(b+i) = i * 100;
        // b[i] = i*100; // equivalent
    }
    for (i = 0; i < 5; i++) {
        printf("%d at %p\n", *(b+i), b+i);
        // printf("%d at %p\n", *(b+i), &(b[i]) );
    }

    // There is a difference between arrays on the stack and arrays on the heap
    // but it is subtle.
    // Both are addresses, but the sizes are different.
    // On the stack, the sizeof is the number of total bytes (so it 
    // contains information about the length)
    printf( "Is a an address? Yes if %p==%p, number of bytes for a = %lu\n", a, &(a[0]), sizeof(a) );
    printf( "Is b an address? Yes if %p==%p, number of bytes for b = %lu\n", a, &(a[0]), sizeof(b) );

    free(b);
    
    long int*c;
    c = malloc(5 * sizeof(long int));
    for (i = 0; i < 5; i++) {
        *(c+i) = i * 1000;
    }
    for (i = 0; i < 5; i++) {
        printf("%ld at %p\n", *(c+i), c+i);
    }
    
    printf( "opposites? %p %p\n", &*c, c );
    free(c);
    
    return 0; 
}