// array.c: illustrates using arrays in C (and C++)

#include <stdio.h>
#include <assert.h>

#define PART1_ONLY 0

enum { MAX = 100 };             // C-friendly alternative for constant integers

int integers[MAX];
double floats[MAX];

void display4(double*, char*);

int main()
{
   assert(sizeof(int) == sizeof(*integers));
   assert(sizeof(double) == sizeof(*floats));

   printf("Size of integer: %d\n", sizeof(int));
   printf("Size of double:  %d\n", sizeof(double));

   printf("Addresses:\n");
   printf("integers:\t%x\t\tintegers[8]:\t%x\n",
          integers, integers + 8);
   printf("         \t%d\t\t            \t%d\n",
          integers, integers + 8);
   printf("floats:  \t%x\t\tfloats[8]:  \t%x\n",
          floats, floats + 8);
   printf("         \t%d\t\t            \t%d\n",
          floats, floats + 8);



#if ! PART1_ONLY
   printf("\n\n");
   display4(floats, "Initial values");
   *(floats + 2) = 99;
   display4(floats, "After *(floats + 2) = 99");
   *(2 + floats) = 0.5;
   display4(floats, "After *(2 + floats) = 0.5");
   2[floats] = 1e20;
   display4(floats, "After [2]floats = 1e20");

   double *fp = &floats[1];
   fp += 2;
   printf("\nAfter setting fp to &floats[1] + 2: fp = %x, *fp = %g\n\n", fp, *fp);
   *fp = 3.1;
   display4(floats, "After *(floats + 3) = 3.1");
#endif
}

void display4(const double *nums, const char *msg)
{
   printf("%s:\n", msg);
   printf("[0]: %6g\t[1]: %6g\t[2]: %6g\t[3]: %6g\n",
          nums[0], nums[1], nums[2], nums[3]);
}