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  1. #include <string>
  2. #include <iostream>
  3. #include <cmath>
  4. #include <stdexcept>
  5.  
  6. double string_to_double(std::string s, unsigned short radix)
  7. {
  8.     std::size_t decimal_pos = s.find('.');
  9.     int decimals = 0;
  10.     if(decimal_pos != std::string::npos)
  11.     {
  12.         s.erase(decimal_pos, 1);
  13.         decimals = s.size() - decimal_pos;
  14.     }
  15.     size_t errpos;
  16.     double answer = stoll(s, &errpos, radix) / std::pow(radix, decimals);;
  17.     if(errpos < s.size())
  18.         throw std::invalid_argument("parse error in string_to_double");
  19.     return answer;
  20. }
  21. int main()
  22. {
  23.     std::cout << string_to_double("10.A",16) << '\n'
  24.               << string_to_double("1001.1",2) << '\n'
  25.               << string_to_double("123.4",10) << '\n'
  26.               << string_to_double("-.123",10) << '\n'
  27.               << string_to_double("abc",16) << '\n'
  28.               << string_to_double("111",2) << '\n';
  29.  
  30. }
  31.  
Success #stdin #stdout 0s 3032KB
comments (?)
stdin
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Standard input is empty
stdout
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16.625
9.5
123.4
-0.123
2748
7
https://ideone.com/QFfESx
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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