#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(unsigned(time(0))); // randomize
}
}
int RandGen::RandInt(int max)
// precondition: max > 0
// postcondition: returns int in [0..max)
{
return 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() / (double(RAND_MAX) + 1);
}
double RandGen::RandReal(double low,double max)
// postcondition: returns double in [low..max)
{
double zeroToOne=rand() / (double(RAND_MAX) + 1);
return (max-low)*zeroToOne+low;
}