//
// File:  RandDef.cpp
// Source file of definitions of random number generating functions
// 

#include "RandDef.h"

//
// Function to seed the random number generator
// Pre:  none
// Post: Random number generator has been seeded.
// 
   
void SeedRand(void)   
{   
   srand( unsigned(time((time_t *)NULL)) );   
}   

//   
// Function to return a random double between 0 and 1     
// Pre:  The generator is seeded.   
// Post: A random double greater than or equal to 0      
//       and less than 1 has been returned.   
//    
    
double random_double(void)    
{   
   return ( rand() / (double(RAND_MAX) + 1) );
}   

//   
// Function to generate a random double between LowerBound 
// and UpperBound   
// Pre:  LowerBound and UpperBound are of type double with   
//       LowerBound < UpperBound.  The generator is seeded.   
// Post: A random double greater than or equal to LowerBound      
//       and less than UpperBound has been returned.   
//    
   
double random_double_range(double LowerBound, double UpperBound)   
{   
   double random_0_1;   // random number between 0 and 1
   
   random_0_1 = rand() / (double(RAND_MAX) + 1);
   return ((UpperBound - LowerBound) *  random_0_1 
            + LowerBound);
}   

//   
// Function to generate a random integer between 
// 0 and UpperBound - 1   
// Pre:  UpperBound is a positive integer. The generator is seeded.   
// Post: A random integer between 0 and UpperBound - 1    
//       has been returned.   
//    
   
int random_int(int UpperBound)   
{   
   double random_0_1;   // random number between 0 and 1 
   
   random_0_1 = rand() / (double(RAND_MAX) + 1);   
   return int(UpperBound * random_0_1);   
}   
   
//   
// Function to generate a random integer between     
// LowerBound  and UpperBound - 1   
// Pre:  LowerBound and UpperBound are integers with   
//       LowerBound < UpperBound.  The generator is seeded.   
// Post: A random integer between LowerBound and     
//       UpperBound - 1 has been returned.   
//    
   
int random_int_range(int LowerBound, int UpperBound)   
{   
   double random_0_1;   // random number between 0 and 1 
   
   random_0_1 = rand() / (double(RAND_MAX) + 1);   
   return int((UpperBound - LowerBound) * random_0_1    
            + LowerBound);   
}