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  1. #include <iostream>
  2. #include <string>
  3. #include <mutex>
  4. #include <thread>
  5. #include <map>
  6.  
  7. std::map<std::string, std::string> map1 ( {{"apple","red"},{"lemon","yellow"}} );
  8. static auto const map_it_end = map1.end();
  9. std::mutex mtx1;
  10.  
  11. void func() {
  12.     std::lock_guard<std::mutex> lock1(mtx1);
  13.  
  14.     auto it1 = map1.find("apple");
  15.     if(it1 != map_it_end)	// instead of: if(it1 != map1.end())
  16.         std::cout << it1->second << ", ";
  17. }
  18.  
  19. int main ()
  20. {
  21. 	auto it1 = map1.end();
  22. 	map1["aaa"] = "bbb";
  23. 	auto it2 = map1.end();
  24.  
  25. 	std::cout << std::endl << std::boolalpha << (it1 == it2) << std::endl;
  26.  
  27.  
  28.     std::thread t1(func);
  29.     std::thread t2(func);
  30.     t1.join();
  31.     t2.join();
  32.  
  33.     return 0;
  34. }
Success #stdin #stdout 0s 20872KB
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stdin
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Standard input is empty
stdout
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true
red, red,
https://ideone.com/tATn0H
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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