Data Structure in C++

Doubly Linked Lists of ints

This is my code below: dlist.cc

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#include #include "dlist.h"

typedef dlist::node node;

dlist::node* dlist::at(int n){ node* c = _head; while(n > 0 && c){ c = c->next; n--; } return c; }

void dlist::insert(node* previous, int value){ node* n = new node{value, previous->next, previous}; previous->next = n; n->next->prev = n; }

void dlist::del(node* which){ node* nn = which->next; which->next = nn->next; delete nn; }

void dlist::push_back(int value){ node* n = new node{value, _tail, _tail->prev}; _tail->prev->next = n; _tail->prev-> n; }

void dlist::push_front(int value){ node* n = new node(value, nullptr); _head->prev = n; _head-> n; }

void dlist::pop_front(){ node* n = _head; _head = _head->next; delete n; }

void dlist::pop_back(){ node* n = _tail; _tail = _tail->prev; delete n; }

bool dlist::empty(){ return size == 0; }

/* out next;

while (c != l.tail()){ out value; out next; } out

bool operator== (dlist&a, dlist&b){ if(a.getSize() != b.getSize()){ return false; }

node* c1 = a.head(); node* c2 = b.head();

while(c1 != a.tail() && c2 != b.tail()){ if(c1->value != c2->value){ return false; }

c1 = c1->next; c2 = c2->next; }

return true; }

dlist operator+ (dlist&a, dlist&b){ dlist l; node* c = a.head(); node* d = b.head();

while(c->next != a.tail()){ l.push_back(c->next->value); c = c->next; }

return l; }

dlist reverse(dlist& l){ dlist a; node* c = l.head();

while(c->next != l.tail()){ a.push_front(c->next->value); c = c->next; }

return a; }

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I have two problems.

1. del() doesn't update the prev pointer.

2. see several syntax errors that would prevent it from compiling successfully.

Please fix and complete my code, and I also need whole code containing main function(list_tests.cc) for testing dlist.cc

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Sample output:

Enter your list values, separated by spaces 1 2 5 8 You entered 4 elements. List 1, 2,5, 8, Verifying Reversed: 8,5, 2,1, Appended 1,2, 5, 8, 1,2, 3, I 1, 2, 3,1, 2, 5, 8 Your list is not 1 2 3. The empty list is empty. Testing list operations. at 1:2 2:5 3:8 insert 1, 104, 103, 102, 101, 100, 2, 5, 8, del 100, 2, 5, 8, push back 100, 2,5, 8,0, push front ,100, 2,5, 8,0, pop back 0, 100, 2, 5, 8, pop front 100, 2, 5, 8, Size is now 4 Verifying List structure is OK