/*
  File: toss.c

  Description:  The user enters the numbers of fair tosses of a coin and the
  program computes the number of heads and tails and prints them out.

  Input: User enters the number of tosses

  Ouput: Displays the number of fair tosses of heads and tails.

  Revised from program 6.9 in Bronson page 313

*/

/* preprocessor include files found in /usr/include/ directory */

#include <stdio.h>   /* needed to call printf() and scanf() */
#include <stdlib.h>  /* needed to call srand() and rand() */
#include <time.h>    /* needed to call the time() function */

/* 
   toss is toss a coin a number of times (which is the input) and returns
   the number of heads, and therefore the number of tails can be computed
*/

/* prototpe declarations */

int tossCoin(int);   
void printStats(int, int);

int main() {

  int numTosses, numHeads;

  /* 
     Generate the first seed value. A NULL arguments forces
     time() to read the computer's internal time in seconds.
     The srand then uses this value to initialize rand()
  */

  srand(time(NULL)); 

  printf("How many tosses of a fair coin shall we do? Please enter: ");

  scanf("%d", &numTosses);

  printf("Ok, you entered %d tosses, so we'd expect %d heads and %d tails\n", numTosses, numTosses/2, numTosses/2);

  numHeads = tossCoin(numTosses);

  printStats(numHeads, numTosses);
  
  return EXIT_SUCCESS;
}

/* printStats function */

void printStats(int heads, int tosses) {

  printf("The number of heads %d, tails %d\n", heads, (tosses-heads));

}


/* tossCoin function */

int tossCoin(int tosses){

  int i;
  int heads = 0;

  for (i=1; i <= tosses; i++) {

    if ((1 + (rand()%100)) <= 50) {
      
      heads++;

    }

  }

  return(heads);

}