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POSorting a Doubly Linked List C++
 

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  1. POSorting a Doubly Linked List C++
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    <p>Trying to do it through a loop that traverses through the list.</p> <p>In the loop I'm feeding the head node into a sorting function that I have defined and then I'm using strcmp to find out if which name in the node should come first. </p> <p>It is not working because writing the names too early. </p> <p>Im comparing them all linearly by going down the list one node at a time and not going back to see if the first should come before the last. That part explained would be helpful.</p> <p>The two functions that are most important to me now are defined as follows: I have tried my best to do what I think is right for the sorting function.</p> <pre><code>void list::displayByName(ostream&amp; out) const { list *ListPtr = NULL; node *current_node = headByName; winery *wine_t = new winery(); // winery is another class object type // im allocating it to prevent a crash when I call it. while ( current_node != NULL ) { *(wine_t) = current_node-&gt;item; wine_t = ListPtr-&gt;sort( current_node ); out &lt;&lt; wine_t &lt;&lt; endl; current_node = current_node-&gt;nextByName; } delete wine_t; } winery * const list::sort( node * current_node ) const { // current_node is the first node. const char *SecondName = NULL, *FirstName = NULL; winery *wine_t = new winery(); if ( current_node != NULL ) { SecondName = current_node-&gt;item.getName(); current_node = current_node-&gt;nextByName; FirstName = current_node-&gt;item.getName(); } if ( strcmp( FirstName, SecondName ) == -1 ) { *(wine_t) = current_node-&gt;item; FirstName = NULL; SecondName = NULL; return wine_t; } else if ( strcmp( FirstName, SecondName ) == 1 ) { *(wine_t) = current_node-&gt;item; FirstName = NULL; SecondName = NULL; return wine_t; } else return wine_t;// then the strings are equal FirstName = NULL; SecondName = NULL; return wine_t; } </code></pre> <p>And I started to develop my nodes here:</p> <pre><code>void list::insert(const winery&amp; winery) { node *current_node = new node( winery ); if ( headByName == NULL ) { headByName = current_node; headByRating = current_node; tail = headByName; current_node-&gt;prev = current_node; } else { current_node-&gt;prev = tail; tail-&gt;nextByName = current_node; } tail = current_node; current_node = NULL; } </code></pre> <p>I think its correct in that function above. Could I possibly get away with sorting it there?</p> <p>Below are my varaibles that I am working with:</p> <pre><code>public list { ... void insert(const winery&amp; winery); void displayByName(ostream&amp; out) const; } private: struct node { node(const winery&amp; winery); // constructor winery item; node * prev; node * nextByName; node * nextByRating; }; winery * const sort(node*) const; node * headByName; node * headByRating; node * tail; }; </code></pre> <p>Any help is appreciated. Thanks very much =)</p>
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    1. CO@lampshade, Instead of posting duplicate http://stackoverflow.com/questions/1309960/linkedlist-part you could correct your original question to add details.
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      1. USKirill V. Lyadvinsky
    2. COWhat the hell is wrong with you?
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    3. COI've contacted the SO team about it.
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