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  1. #include <iostream>
  2. #include <functional>
  3. #include <cctype>
  4. #include <algorithm>
  5. #include <iterator>
  6.  
  7. template <typename InputIterator>
  8. class IteratorWithSkip : public std::iterator<std::forward_iterator_tag, typename InputIterator::value_type>
  9. {
  10. public:
  11.     typedef typename InputIterator::value_type value_type;
  12.     typedef bool (*skip_function)(value_type);
  13.  
  14.     explicit IteratorWithSkip(InputIterator begin, InputIterator end, skip_function f) 
  15.         : m_final(false),  m_it(begin), m_end(end), m_f(f) {}
  16.  
  17.     IteratorWithSkip() : m_final(true) {}
  18.  
  19.     IteratorWithSkip(const IteratorWithSkip& it) : m_it(it.m_it), m_end(it.m_end), m_final(it.m_final), m_f(it.m_f) {
  20.         skip();
  21.     }
  22.  
  23.     IteratorWithSkip& operator=(const IteratorWithSkip& it) {
  24.         if (this != &it) {
  25.             m_it = it.m_it;
  26.             m_end = it.m_end;
  27.             m_final = it.m_final;
  28.             m_f = it.m_f;
  29.         }
  30.         return *this;
  31.     }
  32.  
  33.     IteratorWithSkip operator++(int) { 
  34.         IteratorWithSkip tmp(m_it, m_end, m_f);
  35.         ++(*this);
  36.         return tmp;
  37.     }
  38.  
  39.     IteratorWithSkip& operator++(){
  40.         if (m_it != m_end) ++m_it;
  41.         skip();
  42.         return *this;
  43.     }
  44.  
  45.     bool operator==(const IteratorWithSkip& it) const {
  46.         return (it.m_final && m_it == m_end);
  47.     }
  48.  
  49.     bool operator!=(const IteratorWithSkip& it) const {
  50.         return ! (*this == it);
  51.     }
  52.  
  53.     value_type operator*() {
  54.         return *m_it;
  55.     }
  56. private:
  57.     void skip() {
  58.         while (m_it != m_end && m_f(*m_it)) ++m_it;
  59.     }
  60.     bool m_final;
  61.     InputIterator m_it, m_end;
  62.     skip_function m_f;
  63. };
  64.  
  65. bool is_space (char s)
  66. {
  67.     return isspace(s);
  68. }
  69.  
  70. int main()
  71. {
  72.     std::string s1 = "hello world", s2 = " hellow o r l d   ";
  73.     typedef IteratorWithSkip<std::string::iterator> SkipIterator;
  74.  
  75.     SkipIterator i1(s1.begin(), s1.end(), is_space), i1_end, i2(s2.begin(), s2.end(), is_space);
  76.  
  77.     std::copy (SkipIterator(s2.begin(), s2.end(), is_space), 
  78.                SkipIterator(), 
  79.                std::ostream_iterator<char>(std::cout)); 
  80.  
  81.     std::cout << std::endl;
  82.  
  83.     std::cout << std::boolalpha << std::equal (i1, i1_end, i2) << std::endl;
  84. }
Success #stdin #stdout 0.02s 2860KB
comments (?)
stdin 
Standard input is empty
stdout 
helloworld
true
https://ideone.com/cMCTY
language:
C++ (gcc 8.3)
created:
14 years ago
visibility:
secret

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