A simplified demonstration of what I'm trying to achieve in C++

entry.cpp

#include <store.h>
#include <iostream>

int main() {
  cout << Store.name << endl;
  
  Store.name = "Isaac";
  
  cout << Store.name << endl;
}

prompt.cpp

#include <string>
#include <store.h>

std::string Get() {
  Store.name = "Lucie";
  return "<the string>";
}

store.cpp

#include <store.h>
#include <string>

typedef struct Store {
  std::string name = "Jacob";
};

store.h

#include <string>

extern typedef struct {
  std::string name;
} Store;