Design to avoid binding lvalue reference to temporary for data container and wrapper

I'm struggling with the design of a few (probably two) C++ classes that work together and implement sort of a data container (Vector) and a data wrapper (Integer) that wraps individual vector elements (or better to say the access to it). The Vector simply holds a vector of int. The Integer/wrapper provides access to an int (possibly without holding it).

Requirements:

1. Wrapper/Integer must be available as lvalue
2. The data container should hold the data as an vector of int (not as a vector of Integer)
3. The wrapper also holds some other data members (no reinterpreting cast int -> Integer possible)

I fail to design this (see below) without running into the problem where an lvalue reference cannot bind to a temporary. I understand that that's not possible and I understand that code is wrong (and why it's wrong). There's no need to explain that lvalue references can't bind to rvalues. I'm struggling to find a solution to above requirements without this problem.

How to design this in C++? (Can be any modern standard)

#include<vector>            class Integer  {    int& ref_t;    bool other_data_member;    public:    Integer(int& rhs): ref_t(rhs) {}      Integer& operator=( int i )    {      ref_t = i;      return *this;    }  };        class Vector  {    std::vector<int> data;    public:    Vector(): data(10) {}        Integer& operator[](int i)    {      return Integer( data[i] ); // caution: this doesn't work    }  };        void write_one( Integer& i )  {    i = 1;  }      int main()  {    Vector v;    write_one( v[5] );  }  

https://stackoverflow.com/questions/67215461/design-to-avoid-binding-lvalue-reference-to-temporary-for-data-container-and-wra April 22, 2021 at 10:40PM