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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. struct IPrinter {
  5.     virtual void print(int i, int radix = 10) = 0;
  6.     virtual void print(char c) = 0;
  7.     virtual void print(double d) = 0;
  8.     virtual ~IPrinter() = default;
  9. };
  10.  
  11. struct Printer : public IPrinter {
  12.     void print(int i, int r) override { cout << "int " << i  << ", radix " << r << endl; }
  13.     void print(char c) override { cout << "char " << c << endl; }
  14.     void print(double d) override { cout << "double " << d << endl; }
  15. };
  16.  
  17. class SwitchablePrinter : public IPrinter {
  18.     template <class ... T>
  19.     void print_impl(T ... vals) {
  20.     	 if (_enabled)
  21.     	     _printer.print(vals...);
  22.     	 else
  23.     	     cout << "disabled" << endl;
  24.     }
  25. public:
  26.     SwitchablePrinter(IPrinter& p) : 
  27.         _printer(p), 
  28.         _enabled(true) 
  29.     {
  30.     }
  31.     void print_enable(bool on) { _enabled = on; }
  32.     void print(int i, int r) override {
  33.         print_impl(i, r);
  34.     }
  35.     void print(char c) override {
  36.         print_impl(c);
  37.     }
  38.     void print(double d) override {
  39.         print_impl(d);
  40.     }
  41. private:
  42.     IPrinter& _printer;
  43.     bool _enabled;
  44. };
  45.  
  46. int main() {
  47. 	Printer p;
  48. 	SwitchablePrinter sp(p);
  49. 	sp.print(5, 16);
  50. 	sp.print('c');
  51. 	sp.print(1.5);
  52. 	sp.print_enable(false);
  53. 	sp.print(5, 16);
  54. 	sp.print('c');
  55. 	sp.print(1.5);
  56. 	return 0;
  57. }
Success #stdin #stdout 0s 3464KB
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stdin
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Standard input is empty
stdout
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int 5, radix 16
char c
double 1.5
disabled
disabled
disabled
https://ideone.com/3hQkaT
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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