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  1. #include <iostream>
  2. #include <iomanip>
  3.  
  4. //---------------------------------------------------------
  5.  
  6. template <typename TDerivedClass>
  7. class AbstractLogger {
  8.   public:
  9.     void write(int x);
  10.     void write(double x);
  11.  
  12.     template <typename T>
  13.     void writeLine(T x);
  14. };
  15.  
  16. template <typename TDerivedClass>
  17. void AbstractLogger<TDerivedClass>::write(int x) {
  18.     std::cout << x;
  19. }
  20.  
  21. template <typename TDerivedClass>
  22. void AbstractLogger<TDerivedClass>::write(double x) {
  23.     std::cout << std::setprecision(3) << x;
  24. }
  25.  
  26. template <typename TDerivedClass>
  27. template <typename T>
  28. void AbstractLogger<TDerivedClass>::writeLine(T x) {
  29.     static_cast<TDerivedClass*>(this)->write(x);
  30.     std::cout << std::endl;
  31. }
  32.  
  33. //---------------------------------------------------------
  34.  
  35. class Logger : public AbstractLogger<Logger> {};
  36.  
  37. //---------------------------------------------------------
  38.  
  39. class FooType1 {};
  40. class FooType2 {};
  41.  
  42. class FooLogger : public AbstractLogger<FooLogger> {
  43.   public:
  44.     using AbstractLogger::write;
  45.  
  46.     void write(FooType1 x);
  47.     void write(FooType2 x);
  48. };
  49.  
  50.  
  51. void FooLogger::write(FooType1 x) {
  52.     std::cout << "<value of type FooType1>";
  53. }
  54. void FooLogger::write(FooType2 x) {
  55.     std::cout << "<value of type FooType2>";
  56. }
  57.  
  58. //---------------------------------------------------------
  59.  
  60. int main(int argc, char **argv) {
  61.     FooLogger log;
  62.     FooType1 foo1;
  63.     FooType2 foo2;
  64.  
  65.     log.write(42);           // OK
  66.     log.write(3.14159);      // OK
  67.     log.write(foo1);         // OK
  68.     log.write(foo2);         // OK
  69.  
  70.     std::cout << std::endl;
  71.  
  72.     log.writeLine(42);       // OK
  73.     log.writeLine(3.14159);  // OK
  74.     log.writeLine(foo1);     // OK
  75.     log.writeLine(foo2);     // OK
  76. }
Success #stdin #stdout 0s 15232KB
comments (?)
stdin 
Standard input is empty
stdout 
423.14<value of type FooType1><value of type FooType2>
42
3.14
<value of type FooType1>
<value of type FooType2>
https://ideone.com/nyTliy
language:
C++ (gcc 8.3)
created:
6 years ago
visibility:
public

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