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POSomething weird with operator overloading (C++)
 

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  1. POSomething weird with operator overloading (C++)
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    <pre><code>###MyClass.h### #ifndef _MyClass #define _MyClass #include &lt;string&gt; using namespace std; class MyClass { public: MyClass(const string name, const string text); void display(ostream &amp; out) const; MyClass &amp; operator = (const MyClass &amp; m); int compare(const MyClass &amp; right) const; private: string _name; string _text; }; bool operator &lt; (const MyClass &amp; left, const MyClass &amp; right); ostream &amp; operator &lt;&lt; (ostream &amp; out, const MyClass &amp; mc); #endif ###Node.h### #include &lt;string&gt; #include "MyClass.h" using namespace std; typedef MyClass * DataType; class Node { private: DataType item; // data Node * lchild; // left child pointer Node * rchild; // right child pointer public: Node(DataType Item); DataType getItem() const; void setItem(const DataType &amp; data); Node* getLChild() const; void setLChild(Node * p); Node* getRChild() const; void setRChild(Node * p); virtual ~Node(); }; ###BST.h### #include "Node.h" using namespace std; class BST { private: Node * root; bool Search(const DataType item, Node * r) const; void Insert (DataType item, Node * ptr); void Destructor(const Node * r); public: BST(); bool IsEmpty() const; void Insert(const DataType item); bool Search(const DataType item) const; virtual ~BST(); }; ###MyClass.cpp### #include &lt;iostream&gt; #include "MyClass.h" using namespace std; MyClass::MyClass(const string name, const string text) { _name = name; _text = text; } void MyClass::display(ostream &amp; out) const { out &lt;&lt; "Name: " &lt;&lt; _name &lt;&lt; endl; out &lt;&lt; "Text: " &lt;&lt; _text &lt;&lt; endl; } MyClass &amp; MyClass::operator = (const MyClass &amp; m) { if (this == &amp; m) return *this; _name = m._name; _text = m._text; return *this; } int MyClass::compare(const MyClass &amp; right) const { return _name.compare(right._name); } bool operator &lt; (const MyClass &amp; left, const MyClass &amp; right) { return left.compare(right) &gt; 0; } ostream &amp; operator &lt;&lt; (ostream &amp; out, const MyClass &amp; mc) { mc.display(out); return out; } ###Node.cpp### #include "Node.h" Node::Node(DataType Item):item(Item) { lchild = 0; rchild = 0; } DataType Node::getItem() const { DataType anItem = item; return anItem; } void Node::setItem( const DataType &amp; data) { item = data; } Node* Node::getLChild() const { Node * p = lchild; return p; } void Node::setLChild(Node * p) { lchild = p; } Node* Node::getRChild() const { Node * p = rchild; return p; } void Node::setRChild(Node * p) { rchild = p; } Node::~Node() { } ###BST.cpp### #include &lt;iostream&gt; #include "BST.h" using namespace std; bool BST::Search(const DataType item) const { return Search(item, root); } bool BST::Search(const DataType item, Node * r) const { if(r != 0) { if (item == r-&gt;getItem()) return true; else { if (item &lt; r-&gt;getItem()) return Search(item, r-&gt;getLChild()); else return Search(item, r-&gt;getRChild()); } } else return false; } BST::BST() { root = 0; } bool BST::IsEmpty() const { return (root == 0); } void BST::Insert(const DataType item) { if(root == 0) root = new Node(item); else Insert(item, root); } void BST::Insert(DataType item, Node * ptr) { if (item &lt; ptr-&gt;getItem()) { if (ptr-&gt;getLChild() == 0) ptr-&gt;setLChild(new Node(item)); else Insert(item, ptr-&gt;getLChild()); } else { if (ptr-&gt;getRChild() == 0) ptr-&gt;setRChild(new Node(item)); else Insert(item, ptr-&gt;getRChild()); } } void BST::Destructor(const Node * r) { if(r!=0) { Destructor( r-&gt;getLChild()); Destructor( r-&gt;getRChild()); delete r; } } BST::~BST() { Destructor(root); } ###main.cpp### #include &lt;iostream&gt; #include "MyClass.h" #include "BST.h" using namespace std; void main() { MyClass * mc1 = new MyClass("Tree","This is a tree"); MyClass * mc2 = new MyClass("Book","This is a book"); MyClass * mc3 = new MyClass("Zoo","This is a zoo"); BST * tree = new BST(); tree-&gt;Insert(mc1); tree-&gt;Insert(mc2); tree-&gt;Insert(mc3); cout &lt;&lt; boolalpha &lt;&lt; ("Book" &lt; "Tree") &lt;&lt; endl; cout &lt;&lt; (mc2 &lt; mc1) &lt;&lt; endl; cout &lt;&lt; (tree-&gt;Search(new MyClass("Book",""))) &lt;&lt; endl; } </code></pre> <blockquote> <p>Result is true false false</p> <ol> <li>I don't know what's wrong with my operator overloading? (mc2 should less than mc1)</li> <li>I'm not sure if this is correct for searching a "MyClass" node in a BST? and the result is "not found"....I traced it into "BST.cpp", and found that the problem also occurs at " if (item &lt; r->getItem()) "</li> </ol> <p>Can anyone help me or give me a hint....thank you so much!</p> </blockquote>
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    1. USuser1371541
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    1. CO`void main()` is bad: http://www2.research.att.com/~bs/bs_faq2.html#void-main. There's also no reason for all of your objects to be pointers. Just allocate them on the stack.
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      1. POSomething weird with operator overloading (C++)
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