//https://www.geeksforgeeks.org/expression-tree/
//1) If character is operand push that into stack
//2) If character is operator pop two values from stack make them its child and push current node again.
//At the end only element of stack will be root of expression tree.
public ExpTree(string expression)
{
root = new opNode();
opNode opTemp;
varNode varTemp;
numNode numTemp;
regex = expression;
Queue <string> post = new Queue <string>();
post = postfix();
Stack <Node> expbuilder = new Stack <Node>();
string item = "";
char op;
double num;
var isNumeric = double.TryParse(item, out num);
while (post.Count > 0)
{
item = post.Dequeue();
if (item == "+" || item == "-" || item == "*" || item == "/" || item == "^")
{
opTemp = new opNode();
op = item[0];
opTemp.eexp = op;
opTemp.lleft = expbuilder.Pop();
opTemp.rright = expbuilder.Pop();
expbuilder.Push(opTemp);
}
else
{
isNumeric = double.TryParse(item, out num);
if (isNumeric)
{
numTemp = new numNode();
numTemp.nnumber = num;
expbuilder.Push(numTemp);
}
else
{
varTemp = new varNode();
varTemp.nname = item;
expbuilder.Push(varTemp);
}
}
}
root = expbuilder.Pop();
}
//https://www.geeksforgeeks.org/expression-tree/
//1) If character is operand push that into stack
//2) If character is operator pop two values from stack make them its child and push current node again.
//At the end only element of stack will be root of expression tree.
public ExpTree(string expression)
{
opNode opTemp = new opNode();
varNode varTemp = new varNode();
numNode numTemp = new numNode();
regex = expression;
Queue <string> post = new Queue <string>();
post = postfix();
Stack <Node> expbuilder = new Stack <Node>();
string item = "";
char op;
double num;
var isNumeric = double.TryParse(item, out num);
while (post.Count > 0)
{
item = post.Dequeue();
if (item == "+" || item == "-" || item == "*" || item == "/" || item == "^")
{
opTemp = new opNode();
op = item[0];
opTemp.eexp = op;
opTemp.lleft = expbuilder.Pop();
opTemp.rright = expbuilder.Pop();
expbuilder.Push(opTemp);
}
else
{
isNumeric = double.TryParse(item, out num);
if (isNumeric)
{
numTemp = new numNode();
numTemp.nnumber = num;
expbuilder.Push(numTemp);
}
else
{
varTemp = new varNode();
varTemp.nname = item;
expbuilder.Push(varTemp);
}
}
}
//Added to handle if the expression is just a number or variable like "A1" or just "5"
if (expbuilder.Peek().GetType() == varTemp.GetType())
{
root = new varNode();
root = expbuilder.Pop();
}
else if (expbuilder.Peek().GetType() == numTemp.GetType())
{
root = new numNode();
root = expbuilder.Pop();
}
else if (expbuilder.Peek().GetType() == opTemp.GetType())
{
root = new opNode();
root = expbuilder.Pop();
}
else
{
//ERROR!
}
}