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  1. #include <cstdint>
  2. #include <fstream>
  3. #include <iostream>
  4. #include <string>
  5.  
  6. const std::string program = R"(
  7. +++++ +++++             initialize counter (cell #0) to 10
  8. [                       use loop to set the next four cells to 70/100/30/10
  9.     > +++++ ++              add  7 to cell #1
  10.     > +++++ +++++           add 10 to cell #2 
  11.     > +++                   add  3 to cell #3
  12.     > +                     add  1 to cell #4
  13.     <<<< -                  decrement counter (cell #0)
  14. ]
  15. > ++ .                  print 'H'
  16. > + .                   print 'e'
  17. +++++ ++ .              print 'l'
  18. .                       print 'l'
  19. +++ .                   print 'o'
  20. > ++ .                  print ' '
  21. << +++++ +++++ +++++ .  print 'W'
  22. > .                     print 'o'
  23. +++ .                   print 'r'
  24. ----- - .               print 'l'
  25. ----- --- .             print 'd'
  26. > + .                   print '!'
  27. > .                     print '\n'
  28. )";
  29.  
  30. uint8_t memory[30000];
  31.  
  32. void execute(const std::string& program) {
  33.   auto it = program.begin(), eof = program.end();
  34.   uint8_t* ptr = memory;
  35.   while (it != eof) {
  36.     if (*it == '>') ptr++;
  37.     if (*it == '<') ptr--;
  38.     if (*it == '+') (*ptr)++;
  39.     if (*it == '-') (*ptr)--;
  40.     if (*it == '.') std::cout << *ptr;
  41.     if (*it == ',') std::cin >> *ptr;
  42.     if (*it == '[') {
  43.       if (*ptr == 0) {
  44.         ++it;
  45.         int balance = 0;
  46.         while (*it != ']' || balance != 0) {
  47.           if (*it == '[') ++balance;
  48.           if (*it == ']') --balance;
  49.           ++it;
  50.         }
  51.       }
  52.     }
  53.     if (*it == ']') {
  54.       if (*ptr != 0) {
  55.         --it;
  56.         int balance = 0;
  57.         while (*it != '[' || balance != 0) {
  58.           if (*it == ']') ++balance;
  59.           if (*it == '[') --balance;
  60.           --it;
  61.         }
  62.       }
  63.     }
  64.     ++it;
  65.   }
  66. }
  67.  
  68. int main(int argc, char* argv[]) {
  69.   execute(program);
  70. }
Success #stdin #stdout 0s 4404KB
comments (?)
stdin 
Standard input is empty
stdout 
Hello World!
https://ideone.com/Lpmngq
language:
C++ (gcc 8.3)
created:
3 years ago
visibility:
public

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