How can I get rand to give me proper number using accuracy?

I had a lab where we had to write a program to simulate the duel, for Aaron who a has probability of 1/3, Bob 1/2, Charlie never misses. The program should use random numbers and the probabilities given in the problem to determine whether a shooter hits his target, simulate 10,000 duels.

First time with rand and having some problems with my functions, my professor told me to put the %accuracy so you would only need one function and it would input the players accuracy from the function call, but I am getting an error: invalid operands of types int' anddouble' to binary `operator%', I am confused because accuracy is a number.

I am also having trouble with the while loop because 'fighters' should only subtract one when a player is shot and there will be times when a player is not shot.

#include <iostream>
#include <stdlib.h>
#include <cstdlib>
#include <ctime>

using namespace std;

double rand1 (double accuracy);
bool aaron_shoot (double a, bool& charlie, bool& bob);
bool bob_shoot(double b, bool& charlie, bool& aaron);
bool charlie_shoot (double c, bool& bob, bool& aaron);

int main() {

 bool aaron, bob, charlie; 
 int aaron_wins = 0, bob_wins = 0, charlie_wins = 0; 
 srand(time(0));

   for ( int battles = 1; battles <= 10000; battles++){

      int fighters = 3; 
      while ( fighters > 1){   
        aaron = aaron_shoot(0.333, charlie, bob);          
        bob = bob_shoot (0.5, charlie, aaron);    
        charlie = charlie_shoot (1.0, bob, aaron); 
         //need an argument to make sure a shooter does not shoot if they are dead, and to count             how many are left if there is a hit
} //keeps track of the win at the end of each round of battles when  
  //there is one player left standing       
       aaron_wins = aaron_wins + aaron;
       bob_wins = bob_wins + bob;         
       charlie_wins = charlie_wins + charlie;          
 }
 cout << "Aaron won " << aaron_wins<< "/10000 duels or " << (aaron_wins/100)<< "%.\n";
 cout << "Bob won " << bob_wins << "/10000 duels or " << (bob_wins/100)<<"%.\n";
 cout << "Charlie won " << charlie_wins << "/10000 duels or " << (charlie_wins/100)<<"%.\n";

system ("Pause"); 
return 0;

}


bool aaron_shoot (double a, bool& charlie, bool& bob){
 if (charlie == true){ //is alive
             if (rand1 (a) >= a){
                       return (charlie = false);                           
                       }
             }
 else if (bob == true){
              if (rand1 (a) >= a){
                        return (bob = false);

                        }
              }          
}

bool bob_shoot (double b, bool& charlie, bool& aaron){
 if (charlie == true){
             if (rand1 (b) >= b){
                       return (charlie = false);

                       }
             }
 else if (aaron == true){
              if (rand1 (b) >= b){
                        return (aaron = false);

                        }
              }      
}   

bool charlie_shoot (double c, bool& bob, bool& aaron){
 if (bob == true){
             if (rand1 (c) >= c){
                      return (bob = false);
                       }
             }
 else if (aaron == true){
              if (rand1 (c) >= c){
                        return (aaron = false);

                        }
              }          
}

double rand1 (double accuracy){
   double r = rand ();            
   return (r / RAND_MAX) < accuracy;

}

Solution

double rand1 (double accuracy){
   srand(time(0));
   int a = rand ()% accuracy; <-- THIS
   double b = ((double)a / RAND_MAX);
   return b;
}

I'm not sure what you think that line does, but it doesn't make any sense. If you want to keep the accuracies as fractions, use:

    double r = rand ();
    if ( (r / RAND_MAX) < accuracy)

Also, don't call srand more than once. Otherwise, two calls to rand1 in the same second will get the same return value from rand.