/*--------------------------------------------------------------------*/ 
/*  Problem chapter5_12                                               */ 
/*                                                                    */ 
/*  This program simulates tossing an "fair" coin.                  */ 
/*  The user enters the number of tosses.                             */ 
/*--------------------------------------------------------------------*/ 
 
#include <iostream> 
#include <cstdlib> 
#include <ctime> 
#include <cmath>
using namespace std; 
int rand_int(int , int );   
 
int main() 
{   
   /*  Declare variables and function prototypes.  */   
   int head=0, total=0;   
   
   /*  Prompt user for number of tosses.  */   
   cout << "\nEnter number of fair coin tosses: ";   
   cin >> total;         
   
   srand(time(NULL));
   /* time(NULL) returns seconds from Jan 1, 1970 GMT */

   /*  Toss coin the required number of times, and  */   
   /*  keep track of the number of heads.           */   
   for (int toss=1; toss <= total; toss++)   
        if (rand_int(1,2) == 1)   head++;   
   
   /*  Print results.  */ 
   cout << "\nNumber of tosses:     " << total << endl; 
   cout << "Number of heads:      " << head << endl; 
   cout << "Number of tails:      " << total-head << endl; 
   cout << "Percentage of heads:  " <<  100.0 * head/total << endl; 
   cout << "Percentage of tails:  " <<  100.0 * (total-head)/total << endl; 
 
   /*  Exit program.  */ 
   return 0; 
} 
/*------------------------------------------------------------------*/ 
/*                (rand_int function from page 185)                 */ 
/*  This function generates a random integer                        */ 
/*  between specified limits a and b (a<b).                         */ 
/*------------------------------------------------------------------*/ 
 
int rand_int(int a, int b) 
{ 
   return rand()%(b-a+1) + a; 
}