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  1. #include <iostream>
  2. #include <vector>
  3. #include <random>
  4. #include <functional> //for std::function
  5. #include <algorithm>  //for std::generate_n
  6.  
  7. typedef std::vector<char> char_array;
  8.  
  9. //we don't want a global. That's ugly.
  10. //This will get optimized at compile time anyway
  11. //http://e...content-available-to-author-only...a.org/wiki/Return_value_optimization
  12. char_array charset()
  13. {
  14.     //Change this to suit
  15.     return char_array( 
  16. 	{'0','1','2','3','4',
  17. 	'5','6','7','8','9',
  18. 	'A','B','C','D','E','F',
  19. 	'G','H','I','J','K',
  20. 	'L','M','N','O','P',
  21. 	'Q','R','S','T','U',
  22. 	'V','W','X','Y','Z',
  23. 	'a','b','c','d','e','f',
  24. 	'g','h','i','j','k',
  25. 	'l','m','n','o','p',
  26. 	'q','r','s','t','u',
  27. 	'v','w','x','y','z'
  28. 	});
  29. };    
  30.  
  31. std::string random_string( size_t length, std::function<char(void)> rand_char )
  32. {
  33.     std::string str(length,0);
  34.     std::generate_n( str.begin(), length, rand_char );
  35.     return str;
  36. }
  37.  
  38. int main()
  39. {
  40.     //Independent of character set, 
  41.     //Distribution can be changed
  42.     //Output is non-deterministic
  43.     const auto ch_set = charset();
  44.     std::default_random_engine rng(std::random_device{}()); 
  45.     std::uniform_int_distribution<> dist(0, ch_set.size()-1);
  46.     auto randchar = [ ch_set,&dist,&rng ](){return ch_set[ dist(rng) ];};
  47.     auto length = 5;
  48.     std::cout<<random_string(length,randchar)<<std::endl;
  49.     return 0;
  50. }
Success #stdin #stdout 0s 3432KB
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stdin 
Standard input is empty
stdout 
GBgSi
https://ideone.com/LxhX15
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
secret

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