associativebasics.cpp

C++编程思想第二版第一册答案

//: C20:AssociativeBasics.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Basic operations with sets and maps
#include "Noisy.h"
#include <iostream>
#include <set>
#include <map>
using namespace std;

int main() {
  Noisy na[] = { Noisy(), Noisy(), Noisy(), 
    Noisy(), Noisy(), Noisy(), Noisy() };
  // Add elements via constructor:
  set<Noisy> ns(na, na+ sizeof na/sizeof(Noisy));
  // Ordinary insertion:
  Noisy n;
  ns.insert(n);
  cout << endl;
  // Check for set membership:
  cout << "ns.count(n)= " << ns.count(n) << endl;
  if(ns.find(n) != ns.end())
    cout << "n(" << n << ") found in ns" << endl;
  // Print elements:
  copy(ns.begin(), ns.end(), 
    ostream_iterator<Noisy>(cout, " "));
  cout << endl;
  cout << "\n-----------\n";
  map<int, Noisy> nm;
  for(int i = 0; i < 10; i++)
    nm[i]; // Automatically makes pairs
  cout << "\n-----------\n";
  for(int j = 0; j < nm.size(); j++)
    cout << "nm[" << j <<"] = " << nm[j] << endl;
  cout << "\n-----------\n";
  nm[10] = n;
  cout << "\n-----------\n";
  nm.insert(make_pair(47, n));
  cout << "\n-----------\n";
  cout << "\n nm.count(10)= " 
    << nm.count(10) << endl;
  cout << "nm.count(11)= " 
    << nm.count(11) << endl;
  map<int, Noisy>::iterator it = nm.find(6);
  if(it != nm.end())
    cout << "value:" << (*it).second
      << " found in nm at location 6" << endl;
  for(it = nm.begin(); it != nm.end(); it++)
    cout << (*it).first << ":" 
      << (*it).second << ", ";
  cout << "\n-----------\n";
} ///:~