c++ Recursive Tree building with pointers and a state machine - c++

Question

I have a simple state machine (entered below). My major problem is that I am trying to make a recursive call to the function that is my state machine. What I do upon entry of the function is create a new node for my tree and then push that through. When I do a recursive call, I create a new node over and over. This can work, but when adding children to a parent I'm a little confused. Can someone help look over this and help me take my tree node (parent I'm assuming) and attach a child to it?
TreeNodeClass* ProcessTree(TokenT token, vector <list <stateAssoc> >& vecTree, int depth)
{
int state = 1; //Assume this is a new record.
bool noState = false;
bool update = true;
int dex = 0;
string root, value, data, tag;
TreeNodeClass* treeNode;
treeNode = new TreeNodeClass; //Assume a new node per state machine visit.
//Need 11 to break out of loop as well.
while(state != 10)
{
switch(state)
{
case 1: dex = 1;
break;
case 2: dex = 6;
root = yylval;
break;
case 3: dex = 7;
break;
case 4: dex = 3;
value = yylval;
treeNode->CreateAttrib(root, value);
break;
case 5: dex = 2;
break;
case 6: dex = 4;
data = yylval;
break;
case 7: //Really Don't do anything. Set the tag creation at 8...
dex = 8;
tag = yylval;
if(data != "" and data != "authors")
treeNode->CreateTag(data, tag);
break;
case 8: {
//New TreeNode already grabbed.
//TreeNodeClass* childNode = new TreeNodeClass;
childNode = ProcessTree(token, vecTree, depth+1);
childNode->SetHeight(depth);
treeNode->AddChildren(childNode);
}
token = TokenT(yylex()); //Get a new token to process.
dex = 5;
break;
case 9: dex = 9;
update = false;
if(yylval != treeNode->ReturnTag())
{
state = 11;
}
break;
case 10: update = false;
treeNode->SetHeight(1);
break;
default: cout << "Error " << endl;
cout << state << endl;
cin.get();
break;
}
if(!noState)
state = FindMatch(vecTree[dex], token);
if(update)
token = TokenT(yylex());
else
update = true;
}
return treeNode;
}
You may assume that the dex is simply an index to an array of lists that will return a correct state or 11 (error). Also you may assume that this funciton has atleast been called once on an input file and has started parsing. Thank you for your help.

Answer 1

Looking at your code, you have
int state = 1;
//Code
while(state != 10) {
switch(state) {
case:1 dex = 1; break; //Only case you run
//more cases
case 8: { //never enter here
//New TreeNode already grabbed.
//TreeNodeClass* childNode = new TreeNodeClass;
childNode = ProcessTree(token, vecTree, depth+1);
childNode->SetHeight(depth);
treeNode->AddChildren(childNode); //should work if assuming function is correct
}
//stuff
break;
default: break;//blah
}
}
//blah
return treeNode;
I see no other reason than the fact state is always equal to 1 that your code at case 8 would fail. This is assuming treeNodeClass::AddChildren(TreeNodeClass*) has been properly implemented. WIthout that code, I can assume it's not your problem. Is there some method in which state wouldn't be 1 in the switch?