//**************************************
    //     
    // Name: calculations class
    // Description:class that can solve calc
    //     ulations.
    if we have (2+3)/(25*65+4)+4*4-2^3+4^-2+2^2^0.5
    it will return 10.0655693677103
    // By: silviu petre
    //
    //This code is copyrighted and has    // limited warranties.Please see http://
    //     www.Planet-Source-Code.com/vb/scripts/Sh
    //     owCode.asp?txtCodeId=7650&lngWId=10    //for details.    //**************************************
    //     
    
    using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Globalization;
    namespace SimpleCalc
    {
    public class EvaluateClass
    {
    string DecimalSeparator = ".";
    public string Calculate(string ToCalculate)
    {
    DecimalSeparator = System.Globalization.CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator.ToString();
    string r = ToCalculate;
    try
    {
    if (Verify(ToCalculate))
    {
    ErrorPower = false;
    ToCalculate = Correct(ToCalculate);
    ToCalculate = SolveAllPar(ToCalculate);
    r = Evaluate(ToCalculate);
    if (ErrorPower)
    {
    r = ToCalculate;
    ErrorPower = false;
    }
    }
    }
    catch
    { }
    return r;
    }
    bool ErrorPower = false;
    bool Verify(string x)
    {
    bool v = false;
    bool v1 = false;
    if (ParCheck(x))
    v1 = true;
    bool v2 = false;
    if (!StopEval(x))
    v2 = true;
    if (v1 & v2)
    v = true;
    return v;
    }
    bool ParCheck(string x)
    {
    bool b = false;
    int m = 0, n = 0;
    for (int i = 0; i < x.Length; i++)
    if (x.Substring(i, 1) == "(")
    m++;
    else if (x.Substring(i, 1) == ")")
    n++;
    if (m == n)
    b = true;
    return b;
    }
    bool StopEval(string x)
    {
    bool b = false;
    for (int i = 0; i < x.Length - 1; i++)
    switch (x.Substring(i, 2))
    {
    case "**":
    case "//":
    case "*/":
    case "/*":
    case "+*":
    case "-*":
    case "+/":
    case "-/":
    case "^*":
    case "^/":
    case "*^":
    case "/^":
    b = true; break;
    }
    return b;
    }
    
    string Sum(double[] x, string[] y)
    {
    double r = 0;
    for (int i = 0; i < x.Length; i++)
    {
    if (y[i] == "+")
    r += x[i];
    if (y[i] == "-")
    r -= x[i];
    }
    return Convert.ToString(r);
    }
    bool PartOfNumber(string x)
    {
    string NumberElements = DecimalSeparator + "0123456789";
    bool r = false;
    for (int i = 0; i < NumberElements.Length; i++)
    if (x == NumberElements.Substring(i, 1))
    {
    r = true;
    break;
    }
    return r;
    }
    string Evaluate(string x)
    {
    x = Correct(x);
    if (x.Length > 0)
    if (PartOfNumber(x.Substring(0, 1)))
    x = "+" + x;
    int NrT = 0;
    int NrF = 0;
    bool PON = false;
    bool Last = false;
    for (int i = 0; i < x.Length; i++)
    {
    PON = PartOfNumber(x.Substring(i, 1));
    if (!PON)
    {
    if (x.Length - i > 2)
    if (x.Substring(i, 2) == "E-" | x.Substring(i, 2) == "E+")
    PON = true;
    if (x.Length - i > 1 & i > 0)
    if (x.Substring(i - 1, 2) == "E-" | x.Substring(i - 1, 2) == "E+")
    PON = true;
    if (x.Length - i > 0 & i > 1)
    if (x.Substring(i - 2, 2) == "E-" | x.Substring(i - 2, 2) == "E+")
    PON = true;
    }
    if (i == 0)
    Last = !PON;
    if (Last != PON)
    {
    if (Last)
    NrF++;
    else
    NrT++;
    }
    Last = PON;
    }
    string[] T = new string[NrT];
    string[] F = new string[NrF];
    NrF = -1;
    NrT = -1;
    for (int i = 0; i < x.Length; i++)
    {
    PON = PartOfNumber(x.Substring(i, 1));
    if (!PON)
    {
    if (x.Length - i > 2)
    if (x.Substring(i, 2) == "E-" | x.Substring(i, 2) == "E+")
    PON = true;
    if (x.Length - i > 1 & i > 0)
    if (x.Substring(i - 1, 2) == "E-" | x.Substring(i - 1, 2) == "E+")
    PON = true;
    if (x.Length - i > 0 & i > 1)
    if (x.Substring(i - 2, 2) == "E-" | x.Substring(i - 2, 2) == "E+")
    PON = true;
    }
    if (i == 0)
    Last = !PON;
    if (Last != PON)
    {
    if (Last)
    {
    NrF++;
    F[NrF] += x.Substring(i, 1);
    }
    else
    {
    NrT++;
    T[NrT] += x.Substring(i, 1);
    }
    }
    else
    {
    if (!Last)
    F[NrF] += x.Substring(i, 1);
    else
    T[NrT] += x.Substring(i, 1);
    }
    Last = PON;
    }
    double[] D = new double[T.Length];
    for (int i = 0; i < D.Length; i++)
    D[i] = Convert.ToDouble(T[i]);
    int k = 1;
    for (int i = 0; i < F.Length; i++)
    {
    F[i] = F[i].Replace("*+", "*");
    F[i] = F[i].Replace("/+", "/");
    if (F[i] == "*-" | F[i] == "/-")
    {
    F[i] = F[i].Replace("*-", "*");
    F[i] = F[i].Replace("/-", "/");
    up:
    if (i - k + 1 > 0)
    switch (F[i - k])
    {
    case "+": F[i - k] = "-"; break;
    case "-": F[i - k] = "+"; break;
    case "*":
    case "/": k++; goto up;
    }
    }
    }
    return Power(D, F);
    }
    string Product(double[] x, string[] y)
    {
    int j = 0;
    for (int i = 0; i < y.Length; i++)
    if (y[i] == "+" | y[i] == "-")
    j++;
    double[] D = new double[j];
    string[] F = new string[j];
    j = 0;
    for (int i = 0; i < y.Length; i++)
    {
    if (y[i] == "*")
    D[j - 1] *= x[i];
    if (y[i] == "/")
    D[j - 1] /= x[i];
    if (y[i] == "+" | y[i] == "-")
    {
    D[j] = x[i];
    F[j] = y[i];
    j++;
    }
    }
    return Sum(D, F);
    }
    string Power(double[] x, string[] y)
    {
    int j = 0;
    for (int i = 0; i < y.Length; i++)
    if (y[i] == "+" | y[i] == "-" | y[i] == "*" | y[i] == "/")
    j++;
    double[] D = new double[j];
    string[] F = new string[j];
    j = 0;
    for (int i = 0; i < y.Length; i++)
    {
    if (y[i] == "^")
    {
    if (i > 0)
    {
    if (y[i - 1] == "-" & x[i] % 2 == 0 & x[i] == Math.Truncate(x[i]))
    F[j - 1] = "+";
    else if (y[i - 1] == "-" & x[i] != Math.Truncate(x[i]))
    ErrorPower = true;
    }
    D[j - 1] = Math.Pow(D[j - 1], x[i]);
    }
    else if (y[i] == "^-")
    {
    if (i > 0)
    {
    if (y[i - 1] == "-" & x[i] % 2 == 0 & x[i] == Math.Truncate(x[i]))
    F[j - 1] = "+";
    else if (y[i - 1] == "-" & x[i] != Math.Truncate(x[i]))
    ErrorPower = true;
    }
    D[j - 1] = Math.Pow(D[j - 1], -x[i]);
    }
    else if (y[i] == "+" | y[i] == "-" | y[i] == "*" | y[i] == "/")
    {
    D[j] = x[i];
    F[j] = y[i];
    j++;
    }
    }
    return Product(D, F);
    }
    string Correct(string x)
    {
    for (int i = 0; i < x.Length - 1; i++)
    {
    if (x.Substring(i, 2) == "--" | x.Substring(i, 2) == "++")
    {
    if (i > 0)
    x = x.Substring(0, i) + "+" + x.Substring(i + 2);
    else
    x = "+" + x.Substring(i + 2);
    i--;
    }
    else if (x.Substring(i, 2) == "+-" | x.Substring(i, 2) == "-+")
    {
    if (i > 0)
    x = x.Substring(0, i) + "-" + x.Substring(i + 2);
    else
    x = "-" + x.Substring(i + 2);
    i--;
    }
    }
    return x;
    }
    string SolveAllPar(string x)
    {
    int j = 0;
    for (int i = 0; i < x.Length; i++)
    if (x.Substring(i, 1) == "(")
    j++;
    for (int i = 0; i < j; i++)
    x = SolvePar(x);
    return x;
    }
    string SolvePar(string x)
    {
    int i, j;
    for (i = x.Length - 1; i >= 0; i--)
    if (x.Substring(i, 1) == "(")
    break;
    for (j = i + 1; j < x.Length; j++)
    if (x.Substring(j, 1) == ")")
    break;
    string r = "";
    try
    {
    r = x.Substring(0, i) + Evaluate(x.Substring(i + 1, j - i - 1)) + x.Substring(j + 1);
    }
    catch
    {
    r = x.Substring(0, i) + Evaluate(x.Substring(i + 1, j - i - 1));
    }
    return r;
    }
    }
    }