std::bind与std::function的一些应用

#include <functional>
#include <iostream>
#include <typeinfo>
#include <typeindex>
#include <unordered_map>

class Type {

};

class A {
public:
    static A* instance = nullptr;

    Type GetUint32Type()
    {
        Type type;

        // your businsee
        return type;
    }

    Type GetInt32Type()
    {
        Type type;

        // your businsee
        return type;
    }


    Type* GetInstance()
    {
        if (instance == nullptr) {
            instance = new A();
        }

        return instance;
    } 
};


using CreateType = std::function<Type()>;


std::unordered_map<std::type_index, CreateType> g_typeTable =
{
    {typeid(uint32_t), std::bind(&A::GetUint32Type, A::GetInstance())},
    {typeid(int32_t), std::bind(&A::GetInt32Type, A::GetInstance())}
};

应用场景：使用typeid方法获取类型，根据不同的类型去创建对应的封装。

避免出现大量的if/else