00001 #include "MusimatTutorial.h" 00002 MusimatTutorialSection(B0124) { 00003 Print("*** B.1.24 Recursion ***"); 00004 /***************************************************************************** 00005 00006 B.1.24 Recursion 00007 00008 Recursion means referring back to a value we've calculated previously. Consider the factorial 00009 operation where 5! means 5 x 4 x 3 x 2 x 1. We could use a For statement to calculate factorials. 00010 This function calculates factorials using iteration: 00011 *****************************************************************************/ 00012 00013 para1(); // Step into this function to continue the tutorial 00014 } 00015 00016 Integer factorial(Integer x) { 00017 Integer n = 1; 00018 For (Integer i = x; i > 1; i = i - 1) { 00019 n = n * i; 00020 } 00021 Return(n); 00022 } 00023 00024 Static Void para1() { 00025 00026 /***************************************************************************** 00027 The statement 00028 *****************************************************************************/ 00029 00030 Print(factorial(5)); 00031 00032 /***************************************************************************** 00033 prints 120. 00034 00035 We start with n = 1 and i = 5. The For loop takes the previous value of n, multiplies it by the 00036 current value of i and reassigns the value to n. It then decrements i and performs the operation 00037 repeatedly so long as i > 1. 00038 00039 *****************************************************************************/ 00040 } 00041 00043 /* $Revision: 1.3 $ $Date: 2006/09/05 08:03:08 $ $Author: dgl $ $Name: $ $Id: B0124.cpp,v 1.3 2006/09/05 08:03:08 dgl Exp $ */ 00044 // The Musimat Tutorial © 2006 Gareth Loy 00045 // Derived from Chapter 9 and Appendix B of "Musimathics Vol. 1" © 2006 Gareth Loy 00046 // and published exclusively by The MIT Press. 00047 // This program is released WITHOUT ANY WARRANTY; without even the implied 00048 // warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 00049 // For information on usage and redistribution, and for a DISCLAIMER OF ALL 00050 // WARRANTIES, see the file, "LICENSE.txt," in this distribution. 00051 // "Musimathics" is available here: http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=10916 00052 // Gareth Loy's Musimathics website: http://www.musimathics.com/ 00053 // The Musimat website: http://www.musimat.com/ 00054 // This program is released under the terms of the GNU General Public License 00055 // available here: http://www.gnu.org/licenses/gpl.txt 00056
1.7.2