Looking for Help/Examples for Linked Lists (C++)

PaladinJohn · 2009-06-22T03:05:16

Alright, let me give a little background for those who are interested. Those who are more interested in the code can skip these next two paragraphs. I'm a beginning programmer who just started learning C++ maybe 4 months ago. In my spare time, I run a Table Top game that I designed from the bottom up myself. My friends all love it, but one complaint is that combat is slow and hurts the cinematic feel of the game. I decided that I would kill two birds with one stone and work on my programming while developing aides for my game. As such, I set out to develop the first step in a multi-step project to essentially run the number crunching aspect of combat for my players and leave the cinematic goodness. My problem is, as a novice programmer, I have trouble developing a program if I don't have a good example to work off of. What I'm looking for is a more experienced programmer to either point out the mistake I made with my initial draft and offer some suggestions to fix the problem, or even a good example of what I'm looking to do that I can examine and learn from. The program I have designed is intended to be a Linked List that prompts the user to input a name, and then assign a random number between 1 - 100. As players are added, the linked list sorts the players based on their value until the user chooses to stop adding more players. The linked list then runs through all of the Player objects, displaying the name of the player, and the player's value. Unfortunately, I have never found a good example of a linked list program that has objects that contain two types of member data, and sorts based only on one. I believe I'm close with the current program, but may have made a mistake with a pointer along the way. Also, please note, the current version is not 100% complete. In main() I made it so I could enter in my own value rather than a randomly generated one in order to test and make sure the program was working properly. Since I'm confident in my ability to program that aspect of the program, I am mostly only looking for suggestions in regards to the player class and possibly the linked list itself. Without further ado, here is the source code for my current program: #include <iostream> #include <string> using namespace std; enum { kIsSmaller, kIsLarger, kIsSame}; class Player { public: int CT; string name; Player(string name):myCT(CT){}; ~Player(){} int Compare(const Player&); void Show() { cout << name << ": " << myCT << endl; } private: int myCT; }; int Player::Compare(const Player & theOtherPlayer) { if (myCT < theOtherPlayer.myCT) return kIsSmaller; if (myCT > theOtherPlayer.myCT) return kIsLarger; else return kIsSame; } class Node; class HeadNode; class TailNode; class InternalNode; class Node { public: Node(){} virtual ~Node(){} virtual Node * Insert(Player * thePlayer)=0; virtual void Show() = 0; private: }; class InternalNode: public Node { public: InternalNode(Player * thePlayer, Node * next); virtual ~InternalNode(){ delete myNext; delete myPlayer; } virtual Node * Insert(Player * thePlayer); virtual void Show() { myPlayer->Show(); myNext->Show(); } private: Player * myPlayer; Node * myNext; }; InternalNode::InternalNode(Player * thePlayer, Node * next): myPlayer(thePlayer),myNext(next) { } Node * InternalNode::Insert(Player * thePlayer) { int result = myPlayer->Compare(*thePlayer); switch(result) { case kIsSame: case kIsLarger: { InternalNode * playerNode = new InternalNode(thePlayer, this); return playerNode; } case kIsSmaller: myNext = myNext->Insert(thePlayer); return this; } return this; } class TailNode : public Node { public: TailNode(){} virtual ~TailNode(){} virtual Node * Insert(Player * thePlayer); virtual void Show() { } private: }; Node * TailNode::Insert(Player * thePlayer) { InternalNode * playerNode = new InternalNode(thePlayer, this); return playerNode; } class HeadNode : public Node { public: HeadNode(); virtual ~HeadNode() { delete myNext; } virtual Node * Insert(Player * thePlayer); virtual void Show() { myNext->Show(); } private: Node * myNext; }; HeadNode::HeadNode() { myNext = new TailNode; } Node * HeadNode::Insert(Player * thePlayer) { myNext = myNext->Insert(thePlayer); return this; } class LinkedList { public: LinkedList(); ~LinkedList() { delete myHead; } void Insert(Player * thePlayer); void ShowAll() { myHead->Show(); } private: HeadNode * myHead; }; LinkedList::LinkedList() { myHead = new HeadNode; } void LinkedList::Insert(Player * pPlayer) { myHead->Insert(pPlayer); } int main() { Player * pPlayer; int CT; string name; LinkedList ll; for (;;) { cout << "What Name?: "; cin >> name; cout << "What CT? (0 to stop): "; cin >> CT; if (!CT) break; pPlayer = new Player(name); ll.Insert(pPlayer); } ll.ShowAll(); return 0; } Thank you for your time, I appreciate and look forward to your input!

For Beginners

Started by PaladinJohn June 20, 2009 01:35 AM

10 comments, last by visitor 14 years, 10 months ago

DevFred

840

June 22, 2009 02:16 AM

Quote:Original post by Zahlman
I was sure I remembered seeing something like that, but then I couldn't find it when I tried looking it up. x.x

It's not easy to find.

#include <utility>using namespace std::rel_ops;

visitor

643

June 22, 2009 03:05 AM

Thanks, I didn't know that.

However, while after replacing boost::less_than_comparable with that the direct comparisons with <= and => in code are alright, std::greater<Test> still fails to compile:

C:/MingW/include/c++/3.4.5/bits/stl_function.h:     In member function `bool std::greater<_Tp>::operator()(const _Tp&, const _Tp&) const     [with _Tp = Test]':C:/MingW/include/c++/3.4.5/bits/list.tcc:324:       instantiated from `void std::list<_Tp, _Alloc>::merge(std::list<_Tp, _Alloc>&, _StrictWeakOrdering)     [with _StrictWeakOrdering = std::greater<Test>, _Tp = Test, _Alloc = std::allocator<Test>]'C:/MingW/include/c++/3.4.5/bits/list.tcc:360:       instantiated from `void std::list<_Tp, _Alloc>::sort(_StrictWeakOrdering)     [with _StrictWeakOrdering = std::greater<Test>, _Tp = Test, _Alloc = std::allocator<Test>]'C:\cprograms\Untitled1.cpp:47:   instantiated from hereC:/MingW/include/c++/3.4.5/bits/stl_function.h:218:     error: no match for 'operator>' in '__x > __y'

Or more precisely, it seems it also needs:

using std::rel_ops::operator>;

Is this a problem with library implementation / compiler / C++ namespaces? (I remember vaguely some similar problem with how to get compiler choose user-defined swap method).

Looking for Help/Examples for Linked Lists (C++)

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