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  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <utility>
  5.  
  6. namespace hoge {
  7.  
  8. // intとdoubleを読み込むイテレータ
  9. class my_iter
  10.   : public std::iterator< std::forward_iterator_tag, my_iter> {
  11.  
  12. public:
  13.   // Constructors
  14.   my_iter()
  15.     : stream_(0), eof_(true), values_(std::pair< int, double>()) {
  16.     // デフォルトはeofとする
  17.   }
  18.  
  19.   explicit my_iter(std::istream *stream)
  20.     : stream_(stream), eof_(false), values_(std::pair< int, double>()) {
  21.     read();
  22.   }
  23.  
  24.   // Copy
  25.   my_iter(my_iter const &other)
  26.     : stream_(other.stream_), eof_(other.eof_), values_(other.values_) {
  27.   }
  28.  
  29.   my_iter& operator=(my_iter const &other) {
  30.     if(this != &other) {
  31.       my_iter(other);
  32.       std::swap(*this, other);
  33.     }
  34.     return *this;
  35.   }
  36.  
  37.   // Move
  38.   my_iter(my_iter &&other)
  39.     : stream_(0), eof_(true), values_(std::pair< int, double>()) {
  40.     std::swap(stream_, other.stream_);
  41.     std::swap(eof_, other.eof_);
  42.     std::swap(values_, other.values_);
  43.   }
  44.  
  45.   my_iter& operator=(my_iter &&other) {
  46.     if(this != &other)
  47.       std::swap(*this, other);
  48.     return *this;
  49.   }
  50.  
  51.   // 前置
  52.   my_iter& operator++() {
  53.     read();
  54.     return *this;
  55.   }
  56.  
  57.   // デリファレンス
  58.   std::pair< int, double>& operator*() {
  59.     return values_;
  60.   }
  61.  
  62.   // 比較
  63.   friend bool operator==(my_iter const &lhs, my_iter const &rhs) {
  64.     return lhs.eof_ && rhs.eof_; // 両方がeofだったらイコール
  65.   }
  66.  
  67.   friend bool operator!=(my_iter const &lhs, my_iter const &rhs) {
  68.     return !(lhs == rhs);
  69.   }
  70.  
  71. private:
  72.  
  73.   // 読み込み
  74.   void read() {
  75.     if(!eof_)
  76.       if(!(*stream_).eof()) {
  77.         *stream_ >> values_.first;
  78.         if(!(*stream_).eof())
  79.           *stream_ >> values_.second;
  80.         else
  81.           eof_ = true;
  82.       } else
  83.         eof_ = true;
  84.   }
  85.  
  86.   std::istream *stream_; // ストリーム
  87.   bool eof_; // eofに達したかどうか
  88.   std::pair< int, double> values_; // 読み込んだ値
  89. };
  90.  
  91. } // namespace hoge
  92.  
  93. // ---- MAIN ---
  94.  
  95. using namespace std;
  96. using namespace hoge;
  97. int main() {
  98.   int i=0;
  99.  
  100.   my_iter it(&cin);
  101.   my_iter it_end;
  102.  
  103.   for_each(it, it_end,
  104.     [&i](pair< int, double> const &v) {
  105.       ++i;
  106.       if(v.second < 0.0)
  107.         cout << "fail (line=" << i << ")" << endl;
  108.       else
  109.         cout << v.first << " " << v.second << endl;
  110.     }
  111.   );
  112. }
  113.  
Success #stdin #stdout 0s 2964KB
comments (?)
stdin 
-1 0.2545317407010831
-1 0.4043827251661717
-1 0.0141552946340191
stdout 
-1 0.254532
-1 0.404383
-1 0.0141553
https://ideone.com/n5AKA
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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