#include <stdlib.h>
#include <time.h>

int game(int);
int jackpot();

int main(int argc, char *argv[])
{
  static char buffer[20];
  static int (*function_ptr) (int user_pick);

  if(argc < 2)
  {
    printf("Usage: %s <a number 1 - 20>\n", argv[0]);
    printf("use %s help or %s -h for more help.\n", argv[0], argv[0]);
    exit(0);
  }

// Seed the randomizer
  srand(time(NULL));

// Set the function pointer to point to the game function.
  function_ptr = game;

// Print out some debug messages
  printf("---DEBUG--\n");
  printf("[before strcpy] function_ptr @ %p: %p\n", &function_ptr, function_ptr)
;
  strcpy(buffer, argv[1]);

  printf("[*] buffer @ %p: %s\n", buffer, buffer);
  printf("[after strcpy]  function_ptr @ %p: %p\n", &function_ptr, function_ptr)
;

if(argc > 2)
  printf("[*] argv[2] @ %p\n", argv[2]);
  printf("----------\n\n");

// If the first argument is "help" or "-h" display a help message
  if((!strcmp(buffer, "help")) || (!strcmp(buffer, "-h")))
  {
    printf("Help Text:\n\n");
    printf("This is a game of chance.\n");
    printf("It costs 10 credits to play, which will be\n");
    printf("automatically deducted from your account.\n\n");
    printf("To play, simply guess a number 1 through 20\n");
    printf("    %s <guess>\n", argv[0]);
    printf("If you guess the number I am thinking of,\n");
    printf("you will win the jackpot of 100 credits!\n");
  }
else
// Otherwise, call the game function using the function pointer
  {
    function_ptr(atoi(buffer));
  }
}

int game(int user_pick)
{
  int rand_pick;

// Make sure the user picks a number from 1 to 20
  if((user_pick < 1) || (user_pick > 20))
  {
    printf("You must pick a value from 1 - 20\n");
    printf("Use help or -h for help\n");
    return;
  }

  printf("Playing the game of chance..\n");
  printf("10 credits have been subtracted from your account\n");
/* <insert code to subtract 10 credits from an account> */

// Pick a random number from 1 to 20
  rand_pick = (rand()% 20) + 1;

  printf("You picked:   %d\n", user_pick);
  printf("Random Value: %d\n", rand_pick);

// If the random number matches the user's number, call jackpot()
  if(user_pick == rand_pick)
    jackpot();
  else
    printf("Sorry, you didn't win this time..\n");
}

// Jackpot Function.  Give the user 100 credits.
int jackpot()
{
  printf("You just won the jackpot!\n");
  printf("100 credits have been added to your account.\n");
  /* <insert code to add 100 credits to an account> */
}