137 lines
4.2 KiB
C++
137 lines
4.2 KiB
C++
#include "stlexam.h"
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#pragma hdrstop
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/**************************************************************************
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*
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* memfunc.cpp - Example program for mem_fun and other member function
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* pointer wrappers. See Class Reference Section.
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*
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***************************************************************************
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*
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* (c) Copyright 1994, 1998 Rogue Wave Software, Inc.
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* ALL RIGHTS RESERVED
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*
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* The software and information contained herein are proprietary to, and
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* comprise valuable trade secrets of, Rogue Wave Software, Inc., which
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* intends to preserve as trade secrets such software and information.
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* This software is furnished pursuant to a written license agreement and
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* may be used, copied, transmitted, and stored only in accordance with
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* the terms of such license and with the inclusion of the above copyright
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* notice. This software and information or any other copies thereof may
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* not be provided or otherwise made available to any other person.
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*
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* Notwithstanding any other lease or license that may pertain to, or
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* accompany the delivery of, this computer software and information, the
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* rights of the Government regarding its use, reproduction and disclosure
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* are as set forth in Section 52.227-19 of the FARS Computer
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* Software-Restricted Rights clause.
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*
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* Use, duplication, or disclosure by the Government is subject to
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* restrictions as set forth in subparagraph (c)(1)(ii) of the Rights in
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* Technical Data and Computer Software clause at DFARS 252.227-7013.
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* Contractor/Manufacturer is Rogue Wave Software, Inc.,
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* P.O. Box 2328, Corvallis, Oregon 97339.
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*
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* This computer software and information is distributed with "restricted
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* rights." Use, duplication or disclosure is subject to restrictions as
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* set forth in NASA FAR SUP 18-52.227-79 (April 1985) "Commercial
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* Computer Software-Restricted Rights (April 1985)." If the Clause at
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* 18-52.227-74 "Rights in Data General" is specified in the contract,
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* then the "Alternate III" clause applies.
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*
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**************************************************************************/
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#include <vector>
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#include <functional>
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#include <algorithm>
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#ifdef _RW_STD_IOSTREAM
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#include <iostream>
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#else
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#include <iostream.h>
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#endif
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#ifndef _RWSTD_NO_NAMESPACE
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using namespace std;
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#endif
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//
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// Very large city class
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//
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class MegaPolis
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{
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public:
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MegaPolis(char* s = 0 , float n = 0):cityName(s),population(n) {;}
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// The following function cannot return void due to limitations in
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// some current C++ implementations.
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virtual size_t byPopulation()
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{
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cout<<cityName<<"(MegaPolis)"<<"\t\t\t"<<population<<endl;
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return 0;
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}
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float population;
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protected:
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char* cityName;
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};
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//
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// City and surrounding area class
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//
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class MetroPolis : public MegaPolis
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{
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public:
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MetroPolis(char* s = 0 , float n = 0):MegaPolis(s,n){;}
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virtual size_t byPopulation()
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{
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cout<<cityName<<"(MetroPolis)"<<"\t\t\t"<<population<<endl;
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return 0;
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}
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};
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//
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// Functor compares the size of two MeagPolis classes
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//
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struct GreaterPopulation
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{
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bool operator()(MegaPolis* m1, MegaPolis* m2)
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{
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return m1->population<m2->population;
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}
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} greater_pop;
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int main()
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{
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//
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// Create a vector of very lareg cities
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//
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vector<MegaPolis*, allocator<MegaPolis*> > cityList;
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cityList.push_back(new MegaPolis ("Calcutta",35));
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cityList.push_back(new MegaPolis ("Tokyo",20));
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cityList.push_back(new MegaPolis ("Delhi",10));
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cityList.push_back(new MegaPolis ("Bombay",15));
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cityList.push_back(new MetroPolis ("Cairo",5));
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cityList.push_back(new MetroPolis ("New York",2.5));
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cityList.push_back(new MetroPolis ("Los Angeles",3));
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cityList.push_back(new MetroPolis ("Jakarta",1.5));
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//
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// Now use mem_fun to pass byPopulation member function
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// of MegaPolis to the for_each function.
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//
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cout<<"City "<<" Population (in millions) "<<endl;
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cout<<"----- "<<" -----------------------"<<endl;
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for_each(cityList.begin(),cityList.end(),mem_fun(&MegaPolis::byPopulation));
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cout<<"..............After sorting..........................."<<endl;
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stable_sort(cityList.begin(),cityList.end(),greater_pop);
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for_each(cityList.begin(),cityList.end(),mem_fun(&MegaPolis::byPopulation));
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return 0;
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}
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