} // End function
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Function: recursEval *
* Input: ExpNode *
* Output: double *
* Description: A function that recursively traverse the expresssion*
* tree making the appropriate operations, and returns *
* the result. *
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
public double recursEval(ExpNode currNode)
{
if (currNode == null)
{
return(0);
}
else if (variables.ContainsKey(currNode.getValue()))
{
return(variables[currNode.getValue()]);
}
else
{
switch (currNode.getValue())
{
case "+":
{
return(recursEval(currNode.getLeftChild()) +
recursEval(currNode.getRightChild()));
}
break;
case "-":
{
return(recursEval(currNode.getLeftChild()) -
recursEval(currNode.getRightChild()));
}
break;
case "*":
{
return(recursEval(currNode.getLeftChild()) *
recursEval(currNode.getRightChild()));
}
break;
case "/":
{
return(recursEval(currNode.getLeftChild()) /
recursEval(currNode.getRightChild()));
}
break;
}
return(Double.Parse(currNode.getValue()));
}
} // End function
} // End function
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Function: buildExpTree *
* Input: string[] *
* Output: void *
* Description: A function makes the necessary connections between *
* the nodes, and sets the root of the tree. *
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
public void buildExpTree(string[] postFix)
{
for (int i = 0; i < postFix.Length; i++)
{
if (postFix[i] == "+" || postFix[i] == "-" ||
postFix[i] == "*" || postFix[i] == "/")
{
ExpNode temp1 = ExpTreeStack.Pop();
ExpNode temp2 = ExpTreeStack.Pop();
ExpNode newOperatorNode = new ExpNode(postFix[i]);
newOperatorNode.setLeftChild(temp2);
newOperatorNode.setRightChild(temp1);
ExpTreeStack.Push(newOperatorNode);
}
else
{
ExpTreeStack.Push(new ExpNode(postFix[i]));
}
}
root = ExpTreeStack.Pop();
} // End function
} // End constructor
public ExpTree()
{
root = null;
} // End constructor
new Dictionary <string, double>(); // Dictionary for the variables
// Constructor
public ExpTree(string expression)
{
root = null;
constructTree(expression);
} // End constructor
} // End function
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Function: setLeftChild *
* Input: ExpNode *
* Output: void *
* Description: A function that sets the value of the left child *
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
public void setLeftChild(ExpNode left)
{
leftChild = left; // Sets the left child of the current node
} // End Function
public ExpNode rightChild; // Right child of the node
// Constructor
public ExpNode(string str)
{
value = str;
leftChild = null;
rightChild = null;
} // End constructor
} // End Function
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Function: setRightChild *
* Input: ExpNode *
* Output: void *
* Description: A function that sets the value of the right child *
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
public void setRightChild(ExpNode right)
{
rightChild = right; // Sets the left child of the current node
} // End Function
