Problems with vector manipulation

[IRvineKinneas509@gmail.com]

I'm implementing dijkstra's algorithm, and I'm implementing it using a priority queue so that the shortest distance is on top for fast access. The priority queue uses a vector for its operations, and contains objects of type Node.

Each node has the following properties:

int id
int dist
Node *path

Here is the issue: when I attempt to rearrange the priority queue (i.e. swap two elements during a percolate function to keep the lowest distance on the top), they overwrite eachother. So, let's take this example:

Vector:
[1] = node1
[2] = node2
[3] = node3

Node 3's path points to node 1.

Now when I attempt to swap indexes 3 and 1 using a temp variable and assignment statements, node 1 becomes node 3, and node 3's path member points to itself infinitely, destroying what I have of my path so far.

Summary: I need to be able to swap elements without them overwriting eachother.

Thank you much.

[Paul McKenzie]

Summary: I need to be able to swap elements without them overwriting each other.

Since you didn't show any code, let me start:

// Swap node1 and node2
void swap_nodes(Node* node1, Node *node2)
{
   // fill this in with the code you described
}

Then we will know what exactly you're doing.

Regards,

Paul McKenzie

[IRvineKinneas509@gmail.com]

I have no code for that function because I don't know how to do it. I'm just doing the swap like this:

Node tmp;
tmp = array[i];
array[i] = array[j]
array[j] = tmp;

This overwrites the elements

[Paul McKenzie]

I have no code for that function because I don't know how to do it. I'm just doing the swap like this:

Node tmp;
tmp = array[i];
array[i] = array[j]
array[j] = tmp;-

This overwrites the elements

That, by definition, is exactly what swap is supposed to do, and I see no "overwriting". You are exchanging the exact contents of one Node with the other Node. If you desire the contents to not be exact after this operation, then what you want is not a swap.

Regards,

Paul McKenzie

[Peter_APIIT]

Look for std::swap.

[JohnW@Wessex]

What is the declaration of Node
Do you have a user defined copy constructor and assignment operator?