C:/Musimathics_local/Musimat/MusimatChapter9/C090703b.cpp

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#include "MusimatChapter9.h"
MusimatChapter9Section(C090703b) {
Print("*** Random Real Numbers ***");
/*****************************************************************************

Random Real Numbers

The LCRandom() method returns integers between 0 and c. It is straightforward 
to map its output to any range of Real values between an upper bound U and a 
lower bound L, as shown in the Random function, below.
*****************************************************************************/
        para1(); // Step into this function to continue.
}

Real Random(Real L, Real U) {
        Integer i = LCRandom();                 // get a random integer value
        Real r = Real(i);                               // convert it to a real value
        r = r/Real(c);                                  // scale it to 0.0 <= r < 1.0
        Return(r * (U - L) + L);                // scale it to the range L to U
}

Static Void para1() {
/*****************************************************************************
First, we use LCRandom() to get a random integer. Recall that LCRandom() 
forces the result to be positive. We promote its random integer result to 
Real and store it in r. Next, we divide it by c so its range is 0.0 <= r < 1.0. 
Finally, we scale it by the difference between U and L, and add L, so that 
the random value is bounded above by U and below by L. That way we can get 
a random result from a particular range of values that we can stipulate.

Here is an example of invoking this Real Random() method:
*****************************************************************************/

        Print("*** Ten invocations of Real Random() ***");
        RealList x;
        
        For (Integer i = 0; i < 10; i++ )
                x[i] = Random(0.0, 1.0);

        Print( x );

/*****************************************************************************
This function is declared in MusimatChapter9.h with default values for its
two arguments such that L defaults to 0.0 and U defaults to 1.0.  Thus, to
get a number in the unsigned unit interval [0,1), it suffices to invoke 
Random() without arguments, as follows:
*****************************************************************************/
        Print("*** Various Calls to Real Random() ***");
        Real r = Random();
        Print(r);
        Print("Random(37.5, 37.9)=", Random(37.5, 37.9));

}}

/* $Revision: 1.4 $ $Date: 2006/09/12 17:37:25 $ $Author: dgl $ $Name:  $ $Id: _c090703b_8cpp-source.html,v 1.4 2006/09/12 17:37:25 dgl Exp $ */
// The Musimat Tutorial © 2006 Gareth Loy
// Derived from Chapter 9 and Appendix B of "Musimathics Vol. 1" © 2006 Gareth Loy 
// and published exclusively by The MIT Press.
// This program is released WITHOUT ANY WARRANTY; without even the implied 
// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
// For information on usage and redistribution, and for a DISCLAIMER OF ALL
// WARRANTIES, see the file, "LICENSE.txt," in this distribution.
// "Musimathics" is available here:     http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=10916
// Gareth Loy's Musimathics website:    http://www.musimathics.com/
// The Musimat website:                 http://www.musimat.com/
// This program is released under the terms of the GNU General Public License
// available here:                      http://www.gnu.org/licenses/gpl.txt

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