使用文件的指针读取/编写地图C ++

Question

I'm trying to read and write a std::map object to/from a file. the map type is

map<string, Node*>

and i have successfully written it to a file but unsuccessfully read it back. i'm not sure if i'm storing it correctly i think it's because i have pointers in the map (Node*) but i'm not sure. how can i fully write the entire map with all the objects it contains and then read it back perfectly. my current read/write methods are

Read

template<typename T>
T ReadObject(string path) {
    T num;
    ifstream infile;
    infile.open(path, ios::in|ios::binary);
    infile.read(reinterpret_cast<char *>(&num),sizeof(T));
        infile.close();
    return num;
}

Write

template<typename T>
void WriteObject(string path, T& num) {
       ofstream outfile;
       outfile.open (path, ios::out|ios::binary);
       outfile.write(reinterpret_cast<char *>(&num),sizeof(T));
       outfile.close();
}

btw these work when reading and writing integers

Answer 1

Pointers are just memory addresses. The data you're pointing to is never being placed into the file.

You need to use what you know about the internal structure of the objects when saving them. Bitwise copy is not sufficient.