c++ - Increment operator/ iterator implementation -
i trying figure out couple of things here:
- how write increment operator node class has pointer next node?
how implement iterators class below?
#include <iostream> #include <vector> using namespace std; template <typename t> class node { public: node(int i=0):val(i) {} node*& operator++(int i=0) {return next;}; t val; node *next; }; //================================================ int main() { node<int> *head, *tmp1, *tmp2; tmp1 = new node<int>(0); head = tmp1; (int i=1; i<10; ++i) { tmp2 = new node<int>(i); tmp1->next = tmp2; tmp1 = tmp2; } while (head != null) { cout << head->val << " '"; head = head->operator++(0); //how make work ++head;? } }
this not example demonstrating operator overloading or iterators.
you don't implement operator++ node class; implement iterator. iterator class should separate class.
and please, don't spoil template making assumptions (since val t, constructor should accept t, not int). also, not ignore int parameter operator++ that: dummy used distinguish pre-increment implementation post-increment implementation.
template <typename t> struct node { t val; node *next; node(const t& t = t()) : val(t) {} }; template <typename t> struct node_iter { node<t>* current; node_iter(node<t>* current): current(current) {} const node_iter& operator++() { current = current->next; return *this; } node_iter operator++(int) { node_iter result = *this; ++(*this); return result; } t& operator*() { return current->val; } }; int main() { // make array of nodes, , link them - no point in // dynamic allocation such simple example. node<int> nodes[10]; (int = 0; < 10; ++i) { nodes[i] = node<int>(i); nodes[i].next = (i == 9) ? nodes + + 1 : 0; } // supply pointer first element of array node_iter<int> test(nodes); // , iterate: while (test.current) { cout << *test++ << " "; } // exercise: try linking nodes in reverse order. therefore, create // 'test' pointer last element of array, rather // first. however, not need change while loop, because // of how operator overload works. // exercise: try writing last while loop loop. not use // information number of nodes. } this still long, long way off providing proper data encapsulation, memory management etc. making proper linked list class not easy. that's why standard library provides one. don't reinvent wheel.
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