C++ 去掉const

#include <iostream>
#include <vector>



template<typename T>
class TypeTraits{
private:
    template<typename U> class UnConst{
        public:
            typedef U Result;
    };

    template<typename U> class UnConst<const U>{
        public:
            typedef U Result;
    };

public:
    typedef typename UnConst<T>::Result NonConstType;
};


template<typename T>
using NonConstType =  typename TypeTraits<T>::NonConstType;

template<typename T>
void Func(NonConstType<T> t) {
    std::string* nonP = &t; // ok
    std::string& nonR = t; // ok

    std::cout<<*nonP<<std::endl;
}

// 用于转发函数时，不需要根据参数有无const进行重载函数(函数体实现一样的函数)
template<typename T>
void ForwardFunc(NonConstType<T> t) {
    Func<T>(t);
}


void Test(){
    const int a = 10;
    TypeTraits<const int>::NonConstType noConstVar;

    // int& nonConstRef = a; // error not bind const int to int&
    // int* nonConstP = &a; // error, invaild conversion from const int* to int
    
    int *p = &noConstVar; // ok

    const std::string str("hello");
    ForwardFunc<const std::string>(str);
}


int main(){
    Test();
}