c++ +operator overload

Question

I am try to implement +operator overload for a singly linked list in c++ so I can assign to a new list the sum of 2 list.
exemple:
a = [1 -> 2 -> 3 -> 4]
b = [ 5 -> 6 -> 7 -> 8]
c = a + b // c = [6->8->9->12]

https://code.sololearn.com/cmo96v61P4MT/#cpp

can someone help me debug this code?

Answer 1

For this you will need an assignment constructor, that means you have to overload `operator=`. It will probably involve changing the pointer to your head node.

There are a few pit-falls, especially self-assignment, like `l3 = l3` - make sure this doesn't crash your code. Also consider what happens when `l1 + l2` runs out of scope and the destructor is called. Will `l3` still function?

It's probably best to look up some sample codes online!

Answer 2

Your operator+ only works for Llist, not Llist*. Try stack-allocating your Llists:

int main(){
Llist l1, l2;

for(int i = 0; i<5; i++){
l1.add_tail(i);
l2.add_tail(i);
}

Llist l3 = l1 + l2;

return 0;
}

Answer 3

Nope! overloading + for pointers doesn't work.

But in this case it's not a big deal as all of your nodes are allocated dynamically anyway. Only the Llist struct, a single pointer to the head node, will be on the stack if you stack allocate.

Answer 4

Is there a way to do it with dynamic allocation?

Answer 5

I changed the code a bit and now it's working somehow. https://code.sololearn.com/cmo96v61P4MT/#cpp
The only problem is that when I declare the object and then assign to + operation its not working.
Something like this:
LList l3;
l3 = l1 + l2;

Answer 6

thanks