speciallist.cpp

来自「很经典的书籍」· C++ 代码 · 共 41 行

//: C06:SpecialList.cpp
// Using the second version of transform()
#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <vector>
#include "Inventory.h"
#include "PrintSequence.h"
using namespace std;

struct Discounter {
  Inventory operator()(const Inventory& inv,
    float discount) {
    return Inventory(inv.getItem(),
      inv.getQuantity(),
      int(inv.getValue() * (1 - discount)));
  }
};

struct DiscGen {
  DiscGen() { srand(time(0)); }
  float operator()() {
    float r = float(rand() % 10);
    return r / 100.0;
  }
};

int main() {
  vector<Inventory> vi;
  generate_n(back_inserter(vi), 15, InvenGen());
  print(vi.begin(), vi.end(), "vi");
  vector<float> disc;
  generate_n(back_inserter(disc), 15, DiscGen());
  print(disc.begin(), disc.end(), "Discounts:");
  vector<Inventory> discounted;
  transform(vi.begin(),vi.end(), disc.begin(),
    back_inserter(discounted), Discounter());
  print(discounted.begin(), discounted.end(),
        "discounted");
} ///:~