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

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

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

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

void display4(const double*, const char*);

int main()
{
   // IGNORE: simple santiy check on types
   assert(sizeof(int) == sizeof(*integers));
   assert(sizeof(double) == sizeof(*floats));

   // sizes for to understand following
   printf("Size of integer: %d\n", sizeof(int));
   printf("Size of double:  %d\n", sizeof(double));

   printf("Array addresses:\n");
   printf("integers:\t%x\t\tintegers[8]:\t%x\n",
          integers, integers + 8);
   printf("       base 10: %d\t\t            \t%d\n",
          integers, integers + 8);
   printf("floats:  \t%x\t\tfloats[8]:  \t%x\n",
          floats, floats + 8);
   printf("       base 10: %d\t\t            \t%d\n",
          floats, floats + 8);

   printf("\nContents of array floats:\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;
   *fp = 3.1;
   
   display4(floats, "After fp = &floats[1] + 2, *fp = 3.1");

   return 0;
}

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]);
}