nocompose.cpp

Think in C++ 第二版源码

//: C21:NoCompose.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Writing out the function objects explicitly
#include "copy_if.h"
#include <algorithm>
#include <vector>
#include <string>
#include <iostream>
#include <functional>
#include <cstdlib>
#include <ctime>
using namespace std;

class Rgen {
  const int max;
public:
  Rgen(int mx = 100) : max(RAND_MAX/mx) {
    srand(time(0));
  }
  int operator()() { return rand() / max; }
};

class BoundTest {
  int top, bottom;
public:
  BoundTest(int b, int t) : bottom(b), top(t) {}
  bool operator()(int arg) {
    return (arg >= bottom) && (arg <= top);
  }
};

int main() {
  vector<int> v(100);
  generate(v.begin(), v.end(), Rgen());
  vector<int> r;
  copy_if(v.begin(), v.end(), back_inserter(r),
    BoundTest(30, 40));
  sort(r.begin(), r.end());
  copy(r.begin(), r.end(),
    ostream_iterator<int>(cout, " "));
  cout << endl;
} ///:~