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RECYCLE2.CPP
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1995-02-23
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// File from page 738 in "Thinking in C++" by Bruce Eckel
//////////////////////////////////////////////////
// From the compressed package ECKELT01.ZIP 2/21/95
// Copyright (c) Bruce Eckel, 1995
// Source code file from the book "Thinking in C++",
// Prentice Hall, 1995, ISBN: 0-13-917709-4
// All rights reserved EXCEPT as allowed by the following
// statements: You may freely use this file for your own
// work, including modifications and distribution in
// executable form only. You may copy and distribute this
// file, as long as it is only distributed in the complete
// (compressed) package with the other files from this
// book and you do not remove this copyright and notice.
// You may not distribute modified versions of the source
// code in this package. This package may be freely placed
// on bulletin boards, internet nodes, shareware disks and
// product vendor disks. You may not use this file in
// printed media without the express permission of the
// author. Bruce Eckel makes no
// representation about the suitability of this software
// for any purpose. It is provided "as is" without express
// or implied warranty of any kind. The entire risk as to
// the quality and performance of the software is with
// you. Should the software prove defective, you assume
// the cost of all necessary servicing, repair, or
// correction.
// If you think you've found an error, please
// email all modified files with loudly commented changes
// to: eckel@aol.com (please use the same
// address for non-code errors found in the book).
//////////////////////////////////////////////////
//: RECYCLE2.CPP -- Chapter 14 example w/ RTTI
#include <fstream.h>
#include <stdlib.h>
#include <time.h>
#include <typeinfo.h>
#include "..\14\tstack.h"
ofstream out("recycle2.out");
class trash {
float Weight;
public:
trash(float Wt) : Weight(Wt) {}
virtual float value() const = 0;
float weight() const { return Weight; }
virtual ~trash() {}
};
class aluminum : public trash {
static float val;
public:
aluminum(float Wt) : trash(Wt) {}
float value() const { return val; }
static void value(int newval) {
val = newval;
}
};
float aluminum::val = 1.67;
class paper : public trash {
static float val;
public:
paper(float Wt) : trash(Wt) {}
float value() const { return val; }
static void value(int newval) {
val = newval;
}
};
float paper::val = 0.10;
class glass : public trash {
static float val;
public:
glass(float Wt) : trash(Wt) {}
float value() const { return val; }
static void value(int newval) {
val = newval;
}
};
float glass::val = 0.23;
// Sums up the value of the trash in a bin:
template<class T> void
SumValue(const tstack<T>& bin, ostream& os) {
tstackIterator<T> tally(bin);
float val = 0;
while(tally) {
val += tally->weight() * tally->value();
os << "weight of "
<< typeid(*tally.current()).name()
<< " = " << tally->weight() << endl;
tally++;
}
os << "Total value = " << val << endl;
}
main() {
// Seed the random number generator
time_t t;
srand((unsigned)time(&t));
tstack<trash> bin; // Default to ownership
// Fill up the trash bin:
for(int i = 0; i < 30; i++)
switch(rand() % 3) {
case 0 :
bin.push(new aluminum(rand() % 100));
break;
case 1 :
bin.push(new paper(rand() % 100));
break;
case 2 :
bin.push(new glass(rand() % 100));
break;
}
// Note difference w/ chapter 14: Bins hold
// exact type of object, not base type:
tstack<glass> glassbin(0); // No ownership
tstack<paper> paperbin(0);
tstack<aluminum> ALbin(0);
tstackIterator<trash> sorter(bin);
// Sort the trash:
while(sorter) {
aluminum* ap =
dynamic_cast<aluminum*>(sorter.current());
paper* pp =
dynamic_cast<paper*>(sorter.current());
glass* gp =
dynamic_cast<glass*>(sorter.current());
if(ap) ALbin.push(ap);
if(pp) paperbin.push(pp);
if(gp) glassbin.push(gp);
sorter++;
}
SumValue(ALbin, out);
SumValue(paperbin, out);
SumValue(glassbin, out);
SumValue(bin, out);
}