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Evaluator.cs
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Evaluator.cs
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using System;
using System.Collections.Generic;
namespace callculator
{
public class Evaluator
{
readonly Queue<Token> postfixExpression;
public Evaluator(Queue<Token> postfixExpression)
{
this.postfixExpression = postfixExpression;
}
public double Evaluate()
{
Stack<Token> evaluationStack = new Stack<Token>();
foreach (var token in postfixExpression)
{
if (token.Type == TokenType.Number)
{
evaluationStack.Push(token);
}
else if (token.Type == TokenType.Operator)
{
double result;
Token temp = evaluationStack.Pop();
Operator op = new Operator(token);
if (op.Op.Value == "#" || op.Op.Value == "@")
{
result = op.Operation(double.Parse(temp.Value));
}
else
{
string val1 = evaluationStack.Peek().Value;
result = op.Operation(Double.Parse(evaluationStack.Pop().Value), Double.Parse(temp.Value));
}
evaluationStack.Push(new Token(result.ToString()));
}
else if (token.Type == TokenType.Function)
{
double result = Function.Call(token.Value, evaluationStack);
evaluationStack.Push(new Token(result.ToString()));
}
}
return Double.Parse(evaluationStack.Pop().Value);
}
}
}