//**************************************************************************
// header file for a library of auxiliary utility functions
//**************************************************************************

#ifndef UTILITY_H
#define UTILITY_H

#include <cmath>

const double PI = atan(1.0)*4.0;
const double TOLERANCE = 1.0E-8;  

//************************************************************************
// function to compare two double for "equality". Returns true if they
// are within TOLERANCE of each other.
//************************************************************************
bool dEqual( double x, double y);


//************************************************************************
// function to exchange the values stored in two integer locations
//
// post-condition -- a and b have their values exchanged
//************************************************************************
void swap(int& a, int& b);


//************************************************************************
// function to exchange the values stored in two float locations
//
// post-condition -- a and b have their values exchanged
//************************************************************************
void swap(float& a, float& b);


//************************************************************************
// function to exchange the values stored in two double locations
//
// post-condition -- a and b have their values exchanged
//************************************************************************
void swap(double& a, double& b);


//************************************************************************
// function to return a random integer between 1 and n
//
//  pre-condtion -- n > 0
// post-condition -- the returned value is between 1 and n inclusive
//************************************************************************
int rand(int n);


//************************************************************************
// function to return a random integer between a and b
//
//  pre-condtion -- a > 0, b > 0
// post-condition -- the returned value is between a and b inclusive
//************************************************************************
int rand(int a, int b);


//**************************************************************************
// Function to round a value to n decimal places
//
// post-condition -- returns the rounded value
//**************************************************************************
double round(double value, int n);


//**************************************************************************
// Function to return the distance between two points
//
// parameter usage :
//     x1, y1 -- import the first point
//     x2, y2 -- import the second point
//**************************************************************************
double distance(double x1, double y1, double x2, double y2);


//**************************************************************************
// Function to return true is n is prime
//
// a number is prime if it is not evenly divisible by 
// any number less than it. In this version we only check
// divisors up to the square root of n.
//**************************************************************************
bool prime(int n);


//**************************************************************************
// Function to return true if the character is a vowel
//
// post-condition -- returns true if ch is a vowel and false otherwise
//**************************************************************************
bool isVowel(char ch);

#endif