C++策略模式与函数对象结合应用

struct Strategy {
    virtual ~Strategy() = default;
    virtual void execute() = 0;
};
struct ConcreteStrategyA : Strategy {
void execute() override { / 算法A / }
};
struct Context {
explicit Context(std::unique_ptr<Strategy> s) : strategy(std::move(s)) {}
void run() { strategy->execute(); }
private:
std::unique_ptr<Strategy> strategy;
};

class FlexibleContext {
public:
    using StrategyFunc = std::function<void()>;
explicit FlexibleContext(StrategyFunc func) : strategy(std::move(func)) {}

void run() { strategy(); }

void set_strategy(StrategyFunc func) { strategy = std::move(func); }
private:
StrategyFunc strategy;
};

void function_strategy() { /* 普通函数 */ }
int main() {
FlexibleContext ctx([]{ std::cout << "Lambda strategy\n"; });
ctx.run();
ctx.set_strategy(function_strategy);
ctx.run();

ctx.set_strategy(std::bind(&MyClass::method, myObj));
ctx.run();
}

template<typename Strategy>
class TemplateContext {
public:
    explicit TemplateContext(Strategy s) : strategy(std::move(s)) {}
void run() { strategy(); }
private:
Strategy strategy;
};

auto lambda = [] { std::cout << "Fast lambda\n"; };
TemplateContext ctx(lambda);
ctx.run(); // 内联调用，无开销