|| || || || || || || ||

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RandomGenerator.h

Go to the documentation of this file.

#ifndef Impala_Util_RandomGenerator_h
#define Impala_Util_RandomGenerator_h

#include <ctime>
#include <cstdlib>

namespace Impala
{
namespace Util
{
    
class RandomGenerator
{
public:
    static RandomGenerator&
    GetInstance()
    {
        static RandomGenerator theRandomGenerator;
        return theRandomGenerator;
    }
    
    static void
    RandomizeSeed()
    {
        std::srand(time(0));
    }
    
    static int
    GenerateInt(int i = RAND_MAX)
    {
        return (int) (((double) std::rand() / ((double) RAND_MAX + 1.0)) * (i+1));
    }
    
    static double
    GenerateDouble(double i = 1)
    {
        return (double) (((double) std::rand() / ((double) RAND_MAX + 1.0)) * (i));
    }
    
    static void
    PermutateVector(std::vector<int>& items)
    {
        int endIndex = items.size();
        while(endIndex > 1)
        {
            endIndex--;
            int pick = GenerateInt(endIndex);
            int temp = items[pick];
            items[pick] = items[endIndex];
            items[endIndex] = temp;
        }
    }
    
private:
    // Constructor
    RandomGenerator()
    {
    }
    
    //Copy Constructor
    RandomGenerator(const RandomGenerator&)
    {
    }
    
    // Assignment Operator
    RandomGenerator&
    operator=(const RandomGenerator&)
    {
    }
}; // end class RandomGenerator
    

} // namespace Util
} // namespace Impala

#endif

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