text: #include "strategy.hpp"
  
  #include <memory>
  
  using std::make_shared;
  
  int main()
  {
      auto c = make_shared<Context>();
      auto sa = make_shared<ConcreteStrategyA>();
      auto sb = make_shared<ConcreteStrategyB>();
  
      c->setStrategy(sa.get());
      c->contextInterface();
      c->setStrategy(sb.get());
      c->contextInterface();
  
      return 0;
  }
  
  