//very Important function-=-Self Explainatory
private void PopConnectPush()
{
ExpTreeNode Temp = OpStack.Pop(); //Get Top operator and associate the operands
//Find here if the Operator is "=" - then dont make the Symbol InVALID--Give some value
Temp._right = NodeStack.Pop(); //Get Left and right from NodeStck
if (Temp._value.ToString() == "=")
{
ExpTreeNode TmpLeft = NodeStack.Pop();
//Now this needs to be Symbol with no Sub tree
if (TmpLeft._ndType != ExpTreeNode.NodeType.Symbol)
{
ErrorException Er = new ErrorException("Operator = at the wrong Place Left Operand must be lvalue ");
throw Er;
}
if (TmpLeft._left == null || TmpLeft._right == null)
{
TmpLeft._value = -1; //SYMBOL TO BE CALCULATED
Temp._left = TmpLeft;
NodeStack.Push(Temp); // puch the sub tree on the stack
return;
}
else
{
ErrorException Er = new ErrorException("Operator = at the Wrong Place Left Operand must be lvalue");
throw Er;
}
}
Temp._left = NodeStack.Pop();
NodeStack.Push(Temp); // puch the sub tree on the stack
}
public bool SetExpression(string _exp)
{
//Clear the Previous Exp
_exp_parser.Clear();
//now Parse the Exp
_exp_tree = _exp_parser.ParseExpression(_exp);
return true;
}
public bool SetExpression(string _exp)
{
//Clear the Previous Exp
_exp_parser.Clear();
//Now Parse the Exp
_exp_tree = _exp_parser.ParseExpression(_exp);
return(true);
}
private double _evaluate_exp(ExpTreeNode n)
{
if (n == null)
{
ErrorException Er = new ErrorException("No Expression Tree to Evaluate ");
throw Er;
}
double x, y;
if (n._ndType == ExpTreeNode.NodeType.Operator)
{
x = _evaluate_exp(n._left);
y = _evaluate_exp(n._right);
return((_OpInst == null) ? ApplyOp(n._value.ToString(), x, y):_OpInst.ApplyOp(n._value.ToString(), x, y));
}
return(System.Convert.ToDouble(n._value));
}
private double _evaluate_exp(ExpTreeNode n)
{
if(n== null)
{
ErrorException Er = new ErrorException("No Expression Tree to Evaluate ");
throw Er;
}
double x,y;
if (n._ndType == ExpTreeNode.NodeType.Operator)
{
x = _evaluate_exp(n._left);
y = _evaluate_exp(n._right);
return (_OpInst == null) ? ApplyOp(n._value.ToString(),x,y):_OpInst.ApplyOp(n._value.ToString(),x,y);
}
return (System.Convert.ToDouble(n._value)) ;
}
//not Implemented
public string ReMakeExpression(ExpTreeNode Tree)
{
//Doing nothing right now
return "";
}
public void Push(ExpTreeNode f)
{
data[top++] = f;
}
public TreeStack(int size)
{
data = new ExpTreeNode[size];
top = 0;
}
//Parse Expression funtion main funtion
//Creating the Exp tree from the Infix Expression
public ExpTreeNode ParseExpression(string exp)
{
//Check for the Expresiioon validity
if(!Isvalid_Exp(exp))
{
//Throw an Error Saying Commas are not proper
ErrorException Er = new ErrorException("Operators ( or ) are not at the right places");
throw Er;
//Is c# need this return after that -- i dont think so but anyway
}
//Fill ur _exp Variable will need that
_exp = exp;
NextToken();
do
{
//The errors that might come would be from stack
//If that went wrong -- gone case -- What use rwould do
//no USer specific Errors from this funtion
switch(current)
{
case Token.Literal:
//CreateLeafNode and push it on the stack
ExpTreeNode LNode = new ExpTreeNode();
LNode._value = literal;
LNode._ndType = ExpTreeNode.NodeType.Literal;
NodeStack.Push(LNode);
break;
case Token.Operator:
//pop the St
ExpTreeNode ONode = new ExpTreeNode();
ONode._value = Curr_op;
ONode._ndType = ExpTreeNode.NodeType.Operator;
if(Curr_op == "(")
{
OpStack.Push(ONode);
break;
}
if(Curr_op == ")")
{
while("(" != (string)OpStack.Top._value)
{
PopConnectPush();
}
OpStack.Pop() ; //Throw away {{
break;
}
if(OpStack.IsEmpty())
{
OpStack.Push(ONode);
}
else if((string)OpStack.Top._value == "(")
{
OpStack.Push(ONode);
}
else if(Priority(OpStack.Top._value.ToString()) < Priority(ONode._value.ToString() ))
{
OpStack.Push(ONode);
}
else
{
while(true)
{
PopConnectPush();
if(OpStack.IsEmpty() == true || (string)OpStack.Top._value == "(" || Priority(OpStack.Top._value.ToString() ) < Priority(ONode._value.ToString() ))
break;
}
OpStack.Push(ONode);
}
break;
case Token.Symbol:
{
ExpTreeNode SNode = new ExpTreeNode();
SNode._symbol = symbol;
SNode._ndType = ExpTreeNode.NodeType.Symbol;
NodeStack.Push(SNode);
}
break;
default:
break;
}
}while(NextToken() != Token.Eof);
while(OpStack.IsEmpty() == false)
{
PopConnectPush();
}
//Get the Top of the Node Stack thats the root
return NodeStack.Top;
}
//Not Implemented
public string ReMakeExpression(ExpTreeNode Tree)
{
//Doing nothing right now
return("");
}
public void Push(ExpTreeNode f)
{
data[top++] = f;
}
public TreeStack(int size)
{
data = new ExpTreeNode[size];
top = 0;
}
//Parse Expression funtion main funtion
//Creating the Exp tree from the Infix Expression
public ExpTreeNode ParseExpression(string exp)
{
//Check for the Expresiioon validity
if (!Isvalid_Exp(exp))
{
//Throw an Error Saying Commas are not proper
ErrorException Er = new ErrorException("Operators ( or ) are not at the right places");
throw Er;
//Is c# need this return after that -- i dont think so but anyway
}
//Fill ur _exp Variable will need that
_exp = exp;
NextToken();
do
{
//The errors that might come would be from stack
//If that went wrong -- gone case -- What use rwould do
//No USer specific Errors from this funtion
switch (current)
{
case Token.Literal:
//CreateLeafNode and push it on the stack
ExpTreeNode LNode = new ExpTreeNode();
LNode._value = literal;
LNode._ndType = ExpTreeNode.NodeType.Literal;
NodeStack.Push(LNode);
break;
case Token.Operator:
//pop the St
ExpTreeNode ONode = new ExpTreeNode();
ONode._value = Curr_op;
ONode._ndType = ExpTreeNode.NodeType.Operator;
if (Curr_op == "(")
{
OpStack.Push(ONode);
break;
}
if (Curr_op == ")")
{
while ("(" != (string)OpStack.Top._value)
{
PopConnectPush();
}
OpStack.Pop(); //Throw away {{
break;
}
if (OpStack.IsEmpty())
{
OpStack.Push(ONode);
}
else if ((string)OpStack.Top._value == "(")
{
OpStack.Push(ONode);
}
else if (Priority(OpStack.Top._value.ToString()) < Priority(ONode._value.ToString()))
{
OpStack.Push(ONode);
}
else
{
while (true)
{
PopConnectPush();
if (OpStack.IsEmpty() == true || (string)OpStack.Top._value == "(" || Priority(OpStack.Top._value.ToString()) < Priority(ONode._value.ToString()))
{
break;
}
}
OpStack.Push(ONode);
}
break;
case Token.Symbol:
{
ExpTreeNode SNode = new ExpTreeNode();
SNode._symbol = symbol;
SNode._ndType = ExpTreeNode.NodeType.Symbol;
NodeStack.Push(SNode);
}
break;
default:
break;
}
}while(NextToken() != Token.Eof);
while (OpStack.IsEmpty() == false)
{
PopConnectPush();
}
//Get the Top of the Node Stack thats the root
return(NodeStack.Top);
}