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  1. #include <iostream>
  2. #include <algorithm>
  3. #include <locale>
  4. #include <vector>
  5. #include <iterator>
  6. #include <sstream>
  7.  
  8. struct digits_only: std::ctype<char> 
  9. {
  10.     digits_only(): std::ctype<char>(get_table()) {}
  11.  
  12.     static std::ctype_base::mask const* get_table()
  13.     {
  14.         static std::vector<std::ctype_base::mask> 
  15.             rc(std::ctype<char>::table_size,std::ctype_base::space);
  16. 		for (int i='0'; i<'9'; i++)
  17. 			rc[i] = std::ctype_base::digit;
  18.         return &rc[0];
  19.     }
  20. };
  21.  
  22. int main() {
  23. 	std::string input("123s45dfas6");
  24. 	std::istringstream buf(input);
  25.     buf.imbue(std::locale(std::locale(), new digits_only()));
  26.  
  27.     std::copy(std::istream_iterator<char>(buf), 
  28.         std::istream_iterator<char>(),
  29.         std::ostream_iterator<char>(std::cout, ""));
  30. }
  31.  
Success #stdin #stdout 0.01s 2820KB
comments (?)
stdin 
Standard input is empty
stdout 
123456
https://ideone.com/2M9sp
language:
C++ (gcc 8.3)
created:
13 years ago
visibility:
public

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