Why is there garbage in the variable?

Question

Arduino

Good afternoon!
There is a structure that stores a couple of lines:

struct KeyValue {
  String Key;
  String Value;
  KeyValue* Next;
};

Variable stores a variable of type KeyValue;

KeyValue* Last = &Variable;
KeyValue N = KeyValue { Name, Val, nullptr};
Last->Next = &N;
Last = Last->Next;

Why is there garbage in Last->Key after executing this code?

Answer 1

Because the variable N is local, and ceases to exist after the line:
You should do this:

KeyValue* Last = &Variable;
KeyValue* pN = new KeyValue { Name, Val, nullptr};
Last->Next = pN;
Last = Last->Next;