I am having troubles linking multiple classes together via their pointers - c++

Question

I am having a few simple troubles regarding my code. What I am trying to do is build my own "list" code for 2 reasons. First of all, I want to get a deeper understanding of how linked lists work in practice. And secondly, because I am working on a project that requires a list of references, not just copied objects like the standard "list" library offers. I am also attempting to keep my code similiar to how C# works, while keeping the simplicity of python's naming scheme.
The following code is my issue:
// & - Get the address of object
// * - Get the contents of pointer
// int x = 25;
// int* p = &x;
// "p" now contains the pointer address
// "*p" contains the same info as x
// The following are all equal
// x = x + 5;
// x = *p + 5;
// *p = *p + 5;
template <class T> class Link;
template <class T> class Link {
public:
T result;
bool containsData = false;
Link<T> *x;
};
template <class T> class list {
public:
Link<T> start;
int count = 0;
Link<T> *blank(T object) {
Link<T> temp;
return &temp;
}
void append(T object) {
print("Starting");
Link<T> *temp = &start;
while (true) {
print("1");
if (temp->containsData == false) {
break;
}
print("2");
Link<T> *next = temp->x;
temp = next;
}
print("Doing");
temp->containsData = true;
temp->x = blank(object);
print("Done");
count++;
}
void pop(int index);
void clear();
void reverse();
T get(int index);
};
What is happening is that the first iteration works well. However, the second appended item in the list seems to halt at "1", seeming to be completely incapable of moving past "temp->containsData". I've tried putting it in a try-catch block, but it would seem that not even try-catch picks it up for some reason (Which surprised me quite a bit!). It just exits in the middle of trying to find out if the next item in the list is just another link to search through, or whether it is the last one in the list (Hence, containsData set to false).
I have checked, and yes it is the "temp->containsData" part that just crashes out. It seems trying to access "containsData" randomly crashes it. I am aware the code isn't too pretty, that's mainly from my debugging.
If anyone could throw me some pointers (Pun not-intended) as to how to continue, I would be incredibly grateful. Again, I do not want to just use the inbuilt "list" library and call it a day. I want to legit work through this coding trouble.
Thanking you in advance
Andrey :)

Answer 1

Link<T> *blank(T object) {
Link<T> temp;
return &temp;
}
is bad because it is returning a pointer to non-static local object, which will vanish on returning from this function.
Try this instead:
Link<T> *blank(T object) {
return new Link<T>();
}

Answer 2

Just like magic, the moment I post this, THEN stackoverflow decides to point me to a useful post. I've been looking online for hours!
Thanks for the (Surprisingly) quick responses! I managed to find a better way of doing it. Turns out that I was goind about it a bit of an unnecessarily complicated way. The following code seems to work:
template <class T> class Link {
public:
Link<T> *next;
T *item;
};
template <class T> class list {
public:
Link<T> *start = new Link<T>();
int count = 0;
void append(T *object) {
Link<T> *currentValue = start;
while (currentValue->next != nullptr) {
currentValue = currentValue->next;
}
currentValue->next = new Link<T>();
currentValue->item = object;
print(object);
count++;
}
void pop(int index) {
if (index >= count) { throw "index larger than size!"; }
if (index == 0) {
//Deleting the first item in the list
if (count == 1) {
start = new Link<T>();
} else {
start = start->next;
}
} else if (index == count - 1){
//Deleting the last item in the list
Link<T> *currentValue = start;
while (currentValue->next->next != nullptr) {
currentValue = currentValue->next;
}
currentValue->next = new Link<T>();
} else if (index == count - 1) {
//Deleting somewhere in the middle of the list
}
count--;
}
void clear() { start = new Link<T>(); count = 0; }
T get(int index) {
if (index >= count) { throw "index larger than size!"; }
int looper = 0;
Link<T> *currentValue = start;
while (looper != index) {
currentValue = currentValue->next;
looper++;
}
T *temp = currentValue->item;
return *temp;
}
};
Much smaller, works fine, links everything properly.
HOWEVER, thankyou to all the people pointing out that a pointer will disappear once the reference to it disappears. I completely forgot about that.
Thankyou so much for all your help, and I shall (hopefully) be able to finish this code pretty quickly :)