q3

Node.cpp

#include "Node.h"
#include<iostream>
using namespace std;

Node::Node(int elem){
	data = elem;
	isDataSet = true;
	next = nullptr;
}
Node::Node(void){
	isDataSet = false;
	next = nullptr;
}

Node::~Node(void){}

void Node::add(int elem){
	if(isDataSet)
		get()->next = new Node(elem);
	else{
		data = elem;
		isDataSet = true;
	}
}

void Node::add(Node * elem){
	if(isDataSet)
		get()->next = elem;
	else{
		data = elem->data;
		isDataSet = true;
	}
}

Node * Node::get(int i){
	Node * p = this;
	int ii;
	for(ii = 0 ; ii <= i && p->next ; ii++)
		p = p->next;
	if( ii != i )
		return 0;
	return p;
}

Node * Node::get(){
	Node * p = this;
	while(p->next)
		p = p->next;
	
	return p;
}

void Node::print(){
	if(!isDataSet){
		cout<<"list is empty";
		return ;
	}
	if(next)
		next->print();

	if(data)
		cout<<data;
	else
		cout<<"000";
}

Node.h

#pragma once
class Node
{
private:
	bool isDataSet;
public:
	int data;
	Node * next;
	// constructor
	Node(int);
	Node(void);

	// adding elements to the end of the link list
	void add(int);
	void add(Node*);

	// getting the i-th element
	Node * get(int);

	//getting the last element
	Node * get(); 

	// printing the link list
	void print();

	// destructor
	~Node(void);
};

Source.cpp

#include<iostream>
#include<sstream>
#include "Node.h"
using namespace std;

Node nodify(string str){
	Node res;
	for(int i=str.size()-3;i>-3;i-=3)
		res.add(stoi(str.substr(max(0,i),i<0?i+3:3)));
	return res;
}

Node sum(Node a,Node b){
	Node res,*p,*q;
	p = &a;
	q = &b;
	bool hasCarry=false;
	for( int i = 0 ; p || q ; p = p->next , q = q->next ){
		if(!p)
			p = new Node(0);
		if(!q)
			q = new Node(0);
		int s = p->data + q->data + hasCarry;

		if(s>999){
			hasCarry = true;
			s -= 1000;
		} else
			hasCarry = false;
	
		res.add(s);
	}
	if(hasCarry)
		res.add(1);
	return res;
}

int main(){
	Node aFirst,bFirst,res;
	string a,b;
	
	cin>>a>>b;

	aFirst = nodify(a);
	bFirst = nodify(b);

	res = sum(aFirst,bFirst);
	res.print();
	cout<<endl;

	system("pause");
	return 0;
}