calcinventory.cpp

来自「Thinking in c++ 2nd edition,c++编程思想（第2版）」· C++ 代码 · 共 39 行

//: C06:CalcInventory.cpp
// From "Thinking in C++, Volume 2", by Bruce Eckel & Chuck Allison.
// (c) 1995-2004 MindView, Inc. All Rights Reserved.
// See source code use permissions stated in the file 'License.txt',
// distributed with the code package available at www.MindView.net.
// More use of for_each().
#include <algorithm>
#include <ctime>
#include <vector>
#include "Inventory.h"
#include "PrintSequence.h"
using namespace std;

// To calculate inventory totals:
class InvAccum {
  int quantity;
  int value;
public:
  InvAccum() : quantity(0), value(0) {}
  void operator()(const Inventory& inv) {
    quantity += inv.getQuantity();
    value += inv.getQuantity() * inv.getValue();
  }
  friend ostream&
  operator<<(ostream& os, const InvAccum& ia) {
    return os << "total quantity: " << ia.quantity
              << ", total value: " << ia.value;
  }
};

int main() {
  vector<Inventory> vi;
  srand(time(0));  // Randomize
  generate_n(back_inserter(vi), 15, InvenGen());
  print(vi.begin(), vi.end(), "vi");
  InvAccum ia = for_each(vi.begin(),vi.end(), InvAccum());
  cout << ia << endl;
} ///:~