#include <time.h>                // for time()
#include <stdlib.h>              // for rand/srand
#include "rando.h"

int RandGen::ourInitialized = 0;

RandGen::RandGen()
// postcondition: system srand() used to initialize seed
//                once per program     
{
    if (0 == ourInitialized)
    {
        ourInitialized = 1;      // only call srand once
        srand(time(0));       // randomize
    }
}

RandGen::RandGen(int seed)
// postcondition: system srand() used to initialize seed
//                once per program     
{
    if (0 == ourInitialized)
    {
        ourInitialized = 1;      // only call srand once
        srand(seed);             // randomize
    }
}

void RandGen::SetSeed(int seed)
// postcondition: system srand() used to initialize seed
//                once per program (this is a static function)    
{
    if (0 == ourInitialized)
    {
	ourInitialized = 1;   // only call srand once
	srand(seed);          // randomize
    }
}

int RandGen::RandInt(int max)
// precondition: max > 0
// postcondition: returns int in [0..max)     
{  
    return static_cast<int>(RandReal() * max);
}

int RandGen::RandInt(int low, int max)
// precondition: low <= max     
// postcondition: returns int in [low..max]     
{ 
    return low + RandInt(max-low+1);
}

double RandGen::RandReal()
// postcondition: returns double in [0..1)     
{     
    return rand() / (static_cast<double>(RAND_MAX) + 1); 
}