018
15.08.2005, 08:54 Uhr
FloSoft
Medialer Over-Flow
(Administrator)
|
| Zitat von (un)wissender: |
Man könnte es so machen, es fehlt aber bei virtuals Code noch das friend, oder ähnliches, weil man sonst nicht an den node im iterator kommt.
| C++: |
#include <algorithm>
#include <iostream>
#include <iterator>
#include <memory>
#include <stdexcept>
template<typename T>
class liste {
struct node {
node* prev;
node* next;
T data;
node(const T& data) :prev(this), next(this), data(data) {
}
void unlink() {
prev->next = next;
next->prev = prev;
}
void link(node* prev_node) {
prev = prev_node;
next = prev_node->next;
prev->next = this;
next->prev = this;
}
};
node* root;
public:
class iterator {
friend class liste; //HIER: friend
liste* l;
node* n;
public:
iterator(liste* l=0, node* n=0) :l(l), n(n) { }
T& operator * () { return n->data; }
T* operator -> () { return &n->data; }
iterator operator ++ (int) {
iterator tmp(l,n);
if (n) {
n = n->next;
}
return tmp;
}
iterator& operator ++ () {
if (n) {
n = n->next;
}
return *this;
}
iterator operator -- (int) {
iterator tmp(l,n);
if (n) {
n = n->prev;
}
return tmp;
}
iterator& operator -- () {
if (n) {
n = n->prev;
}
return *this;
}
bool operator != (const iterator& other) const {
return other.l!=l || other.n!=n;
}
bool operator == (const iterator& other) const {
return other.l==l && other.n==n;
}
};
liste() {
root = std::allocator<node>().allocate(1, 0);
root->prev = root->next = root;
}
iterator begin() {
return iterator(this, root->next);
}
iterator end() {
return iterator(this, root);
}
void push_front(const T& data) {
node* n = new node(data);
n->link(root);
}
void push_back(const T& data) {
node* n = new node(data);
n->link(root->prev);
}
void pop_front() {
node* n = root->next;
n->unlink();
delete n;
}
void pop_back() {
node* n = root->prev;
n->unlink();
delete n;
}
void erase(iterator i)
{
iterator current = begin(), ende = end();
while(current != i && i != ende) ++current;
if(current == ende) //nicht gefunden
{
throw std::invalid_argument("Unknown iterator");
}
current.n->unlink();
delete current.n;
}
};
int main() {
liste<int> list;
list.push_back(1);
list.push_back(2);
list.push_back(3);
//@virtual: DAs geht nicht, wegen den fehlenden typedefs "iterator_category, usw."
//std::copy(list.begin(), list.end(), std::ostream_iterator<int>(std::cout, " "));
typedef liste<int>::iterator listIter;
for(listIter i = list.begin(); i != list.end(); ++i)
{
std::cout << *i << " ";
}
list.erase(++list.begin()) ;
std::cout << '\n';
for(listIter i = list.begin(); i != list.end(); ++i)
{
std::cout << *i << " ";
}
}
|
|
jo das friend hab ich schon bemerkt das fehlt. So in der Art hab ichs mir schon gedacht. Danke. Ich hasse templates :P was ich dafür schon an Zeit verbraucht habe, hätte ich die Liste für die 3 Typen einzeln schreiben können 
--
class God : public ChuckNorris { }; |
