00001 #include "MusimatTutorial.h" 00002 MusimatTutorialSection(B0123) { 00003 Print("*** B.1.23 Type Conversion ***"); 00004 /***************************************************************************** 00005 00006 B.1.23 Type Conversion 00007 00008 We can explicitly convert Integer expressions to Real, and vice versa. For example: 00009 *****************************************************************************/ 00010 00011 Real a = 10.0/3.0; 00012 Print(a); 00013 00014 /***************************************************************************** 00015 prints 3.333 . . . , and 00016 *****************************************************************************/ 00017 00018 Integer b = Integer(a); // convert a to Integer 00019 Print(b); 00020 00021 /***************************************************************************** 00022 prints 3. 00023 00024 When assigning a to b, the Real value a is converted to an Integer by truncating (discarding) 00025 the fractional part of a (that is, by discarding 0.333…), and the integer residue (3) is assigned to 00026 b. If we then write 00027 *****************************************************************************/ 00028 00029 Real c = Real(b); 00030 Print(c); 00031 00032 /***************************************************************************** 00033 the integer value of b (which is 3) is converted to the equivalent Real value (3.0), which is stored 00034 in Real variable c. 00035 00036 Converting from Real to Integer, we have some choices. For example, if 00037 *****************************************************************************/ 00038 00039 Real p = 10.0/3.0; // Real variable a is set to 3.333 . . . 00040 00041 /***************************************************************************** 00042 then 00043 *****************************************************************************/ 00044 00045 Real d = Floor(p); // d is set to 3.0 00046 Print(d); 00047 00048 /***************************************************************************** 00049 sets d to 3.0. The built-in Floor() function returns the largest integer less than its Real argu- 00050 ment. The statement 00051 *****************************************************************************/ 00052 00053 Real x = Ceiling(p); 00054 Print(x); 00055 00056 /***************************************************************************** 00057 sets x to 4 because the built-in Ceiling() function returns the smallest integer greater than its 00058 argument. 00059 00060 We can round a Real to the nearest whole number as follows: 00061 *****************************************************************************/ 00062 00063 Real r = Floor(p + 0.5); // round c to the nearest whole number 00064 Print(r); 00065 00066 /***************************************************************************** 00067 If a = 2.4, then Floor(a + 0.5) returns 2.0. But if a = 2.5, Floor(a + 0.5) returns 00068 3.0. Floor(a + 0.5) returns 2.0 for any value a in the range 2.0 to 2.499... and returns 00069 3.0 for any value a in the range 2.5 to 2.999.... But we don't have to do rounding ourselves, 00070 Musimat has a built-in function: 00071 *****************************************************************************/ 00072 00073 Print(Round(2.49999)); // prints 2.0 00074 00075 } 00076 00078 /* $Revision: 1.2 $ $Date: 2006/09/05 06:32:25 $ $Author: dgl $ $Name: $ $Id: B0123.cpp,v 1.2 2006/09/05 06:32:25 dgl Exp $ */ 00079 // The Musimat Tutorial © 2006 Gareth Loy 00080 // Derived from Chapter 9 and Appendix B of "Musimathics Vol. 1" © 2006 Gareth Loy 00081 // and published exclusively by The MIT Press. 00082 // This program is released WITHOUT ANY WARRANTY; without even the implied 00083 // warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 00084 // For information on usage and redistribution, and for a DISCLAIMER OF ALL 00085 // WARRANTIES, see the file, "LICENSE.txt," in this distribution. 00086 // "Musimathics" is available here: http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=10916 00087 // Gareth Loy's Musimathics website: http://www.musimathics.com/ 00088 // The Musimat website: http://www.musimat.com/ 00089 // This program is released under the terms of the GNU General Public License 00090 // available here: http://www.gnu.org/licenses/gpl.txt 00091
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