/*------------------------------------------------------------------*/ 
/*  Problem chapter5_15                                             */ 
/*                                                                  */ 
/*  This program simulates rolling two six-sided "fair" dice.       */ 
/*  The user enter the number of rolls.                             */ 
 
#include <iostream> 
#include <cstdlib> 
#include <ctime> 
using namespace std; 
 
int rand_int(int a, int b); 
 
int main() 
{ 
   /* Declare variables and function prototypes.  */ 
   int count=0, total=0; 
 
   /*  Prompt user for number of rolls.  */ 
   cout << "\n\nEnter number of fair pair-dice rolls: "; 
   cin >> total; 
 
   /*  Roll the die as many times as required  */ 
   srand(time(NULL));
   for (int rolls=1; rolls <= total; rolls++) 
        if ( rand_int(1,6) + rand_int(1,6) == 8 ) 
            count++;
 
   /*  Print the results.  */ 
   cout << "\nNumber of rolls:  " << total << endl; 
   cout << " Percentage where the sum is eight: " << 100.0*count/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; 
}