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  1. #include <iostream>
  2. #include <string>
  3. #include <algorithm>
  4. using namespace std::literals::string_literals;
  5.  
  6. template <class StringType, class Predicate, class SizeType = typename StringType::size_type>
  7. SizeType search(const StringType& where, Predicate pred, SizeType pos, SizeType n)
  8. {
  9. 	if (n > 0 && pos < where.size())
  10. 	{
  11.     	auto start = where.c_str(),
  12.     		 ptr = start + pos,
  13. 	    	 stop = ptr + std::min(where.size() - pos, n);
  14.     	do
  15.     	{
  16.         	if (pred(ptr, stop - ptr))
  17.         		return ptr - start;
  18. 		}
  19. 		while (++ptr < stop);
  20. 	}
  21.     return StringType::npos;
  22. }
  23.  
  24. template <class StringType, class Predicate, class SizeType = typename StringType::size_type>
  25. SizeType search(const StringType& where, Predicate pred, SizeType pos = 0)
  26. {
  27.     return search(where, pred, pos, where.size()-pos);
  28. }
  29.  
  30. int main()
  31. {
  32. 	std::cout << search("Hello world"s,
  33. 		[](auto&& str, auto n) { 
  34.         	return n > 3 &&
  35.         		str[0] == 'l' &&
  36.         		str[1] == 'l'; 
  37.         }
  38. 	) << std::endl;
  39.  
  40. 	std::cout << search(L"Hello world"s,
  41. 		[](auto&& str, auto n) { 
  42.         	return n > 3 &&
  43.         		str[0] == L'l' &&
  44.             	str[1] == L'l'; 
  45.         }
  46. 	) << std::endl;
  47.  
  48. 	return 0;
  49. }
Success #stdin #stdout 0.01s 5536KB
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Standard input is empty
stdout 
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https://ideone.com/C6ABjJ
language:
C++ 4.3.2 (gcc-4.3.2)
created:
2 years ago
visibility:
public

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