Linked List "Calculator" works?

[AmmmG 01]

Good morning guys!
I have really worked hard on this project and I hope
you guys would see what is the problem with it; it is driving me
crazy!

Everything is done, but it is not working somehow!

I really appreciated!!

#include <iostream>
#include <string>
using namespace std;
class Node
{
public:
	int val;
	Node * next;
	Node(){val=0;next=NULL;}
	Node(int v){val=v;next=NULL;}
};

Node Plus(Node* a, Node* b, Node* c)
{
    if(!a && !b) return 0;
    if(!a) return c->val=b->val;
	if(!b) return c->val=a->val;
    if(a->val + b->val >=10)
    {
    return c->val= a->val+b->val-10;
    a->next->val+1;
    }
	Plus(a->next, b->next, c->next);
}
Node Minus(Node* a, Node* b, Node* c)
{
    if(!a && !b) return 0;
    if(!a) return c->val=b->val;
    if(!b)return c->val=a->val;
    if(a->val-b->val<0)
    {
    a->val=a->val+10;
	c->val = a->val-b->val;
    a->next->val-1;
    }
	else {
    c->val = b->val-a->val;
    }
    Minus(a->next,b->next, c->next);
}
void Print(Node *h)
{
	while(h)
	{
		cout<<h->val;
		h=h->next;
	}
}
void AddHead(Node*& h, int v)
{
	Node *a = new Node(v);
	a->next = h;
	h=a;
}
int Length(Node *h)
{
	int i=0;
	while(h)
	{
		i++;
		h=h->next;
	}
	return i;
}
void DeleteHead(Node*&h)
{
	if(!h) return;
	Node *t = h;
	h=h->next;
	delete t;
}


int main()
{
	Node* answer = NULL;
	string num1="", num2="";
	char ansdo, ansop;
	do{
	cout<<"Enter the first number:";
	cin>>num1;

	const char *in = num1.c_str();
	int i=0;
	Node * head1 = NULL;
	while(in[i]!='\0')
	{
		int value = in[i]-'0';
		AddHead(head1, value);
		i++;
	}

	cout<<"Enter the second number:";
	cin>>num2;

	const char *in2 = num2.c_str();
	int j=0;
	Node * head2 = NULL;
	while(in[j]!='\0')
	{
		int value = in[j]-'0';
		AddHead(head2, value);
		i++;
	}

	cout<<"Enter + to add or - to subtract: ";
	cin>>ansop;
	
	if ( ansop == '+')
	{
	answer = Plus(head1,head2,answer);
	Print(answer);
	}
    else if (ansop == '-')
		{
		if (Length(head1)>Length(head2))
		{
		head1->val-head2->val;
		Print(answer);
		}
		else
		{
		Node* tmp=head1;	
	    head1=head2;
		head2=tmp;
		Minus(head1,head2, answer);
        }
		}
	else cout<<"Wrong Input!"<<endl;
	
	cout<<"Would you like to repeat the calculation? <Y to repeat>:";
	cin>>ansdo;
} while(ansdo == 'y' && ansdo == 'Y');

	return 0;
}

[AmmmG 01]

The problem is in int main()
and it is basically saying that "cannot change node to node*"

maybe other guys can help?

[Moschops]

answer = Plus(head1,head2,answer);

This function, Plus, returns a Node object.

answer is not a Node object. It is a pointer-to-Node. So you're trying to take the Node object returned from the function and assign it to answer, which is impossible, because answer isn't a Node. You cannot store a Node in a Node-pointer object. A Node-pointer object is for storing the address of a Node; it is not for storing a Node.

[AmmmG 01]

Thanks Moschops.

But how to fix it?

I am still a sophmore, and I have done a whole lot of sweat and tears for this project
and I sincerely hope you would fix it for me! thanks!

[alex067]

the Plus function returns an object of that datatype, so basically what you would get is ANOTHER object datatype which is the result of head1 + head2

I don't know why you just don't use the node values?

you can just do a basic addition of a->val + b->val and store it in an int, then RETURN this int

[AmmmG 01]

Thanks, I just fixed the addition!

Can you look at the Minus/subtraction function and see why is it not working?

Thanks!