链表选择排序算法中的逻辑错误

Question

I have gotten it to consistently work with 3 nodes, but when I raise it to 10 nodes, I get a stack that is partially sorted. The linked list class that this is attatched to definitely works properly, and I have gotten bubbleSort working properly so far. first points to the first node in the list, last to the last. count is the number of nodes in the linked list. firstNode is the node I use to hold the sorted list, so anything before it should contain all of the smallest nodes already sorted. I keep it on the last node in the sorted portion so I can replace it's link when the next node is found. I have gone over this code several times on paper, and can't seem to find the error.

template<class Type>
void unorderedLinkedList<Type>::selectionSort()
{
    nodeType<Type> *tempNode, *traverseNode, *preNode, *firstNode;
    tempNode=first; //initializing Nodes
    traverseNode = first;
    preNode = first;
    for (int i = 0; i < count - 1; i++) //loops 1 time for setting first Node
    {
        if (tempNode->info > traverseNode->link->info) // checks for smallest Node
        {
            preNode = traverseNode;
            tempNode = traverseNode->link;
        }
        traverseNode = traverseNode->link;
    }
    if (tempNode != first) //places smallest Node in position first
    {
        if (tempNode != last) //check if tempNode is last
            preNode->link = tempNode->link;
        else
        {
            preNode->link = NULL;
            last = preNode;
        }
        tempNode->link = first;
        first = tempNode;
    }

    firstNode = first;
    for (int iteration = 2; iteration < count; iteration++) //loop that should place element into the next slot each iteration
    {
        preNode = firstNode;
        tempNode = firstNode->link;
        for (int index = 0; index < count - iteration; index++) //loop that should find the smallest element
        {
            traverseNode = firstNode->link;
            if (traverseNode->link->info < tempNode->info) //checking if node is smaller
            {
                preNode = traverseNode;
                tempNode = traverseNode->link;
            }
            traverseNode = traverseNode->link; //traverse to next node
        }
        if (tempNode != last) //check if node is the last node  
            preNode->link = tempNode->link;
        else
        {
            preNode->link = NULL;
            last = preNode;
        }
        tempNode->link = firstNode->link; //node swap
        firstNode->link = tempNode;
        firstNode = firstNode->link;
    }
} //end selectionSort

Answer 1

This line

traverseNode = firstNode->link;

needs to be outside of your inner for loop (the one on index ). Otherwise you are always just comparing against the same node.

Edit: You are also missing a test for when you don't have to swap nodes. Your second inner loop and subsequent link manipulation should look like your first loop (in fact, you may be able to simplify and use the same code for both)