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  1. #include <iostream>
  2. #include <functional>
  3.  
  4. std::function<int(int)> gen_fun(int n) {
  5.     return [&n](int x) { return x*n; };
  6. }
  7.  
  8. std::function<int(int)> right_gen_fun(const int &n) {
  9.     return [&n](int x) { return x*n; };
  10. }
  11.  
  12. void TestDefault() {
  13.     std::function<int(int)> f = gen_fun(5);
  14.     std::cout << f(1) << std::endl;
  15.     std::cout << f(2) << std::endl;
  16.     std::cout << f(3) << std::endl;
  17. }
  18.  
  19. void TestRight() {
  20.     std::function<int(int)> f = right_gen_fun(5);
  21.     int value = 0;
  22.     std::cout << f(++value) << std::endl;
  23.     std::cout << f(++value) << std::endl;
  24.     std::cout << f(++value) << std::endl;
  25. }
  26.  
  27. int main() {
  28.   TestDefault();
  29.   TestRight();
  30. }
Success #stdin #stdout 0s 3464KB
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https://ideone.com/XlApi6
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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