Is there an eval function In C#?

Question

I'm typing an equation into a TextBox that will generate the graph of the given parabola. Is it possible to use an eval function? I'm using C# 2010 and it doesn't have Microsoft.JScript

Answer 1

C# doesn't have a comparable Eval function but creating one is really easy:

public static double Evaluate(string expression)  
       {  
           System.Data.DataTable table = new System.Data.DataTable();  
           table.Columns.Add("expression", string.Empty.GetType(), expression);  
           System.Data.DataRow row = table.NewRow();  
           table.Rows.Add(row);  
           return double.Parse((string)row["expression"]);  
       }

Now simply call it like this:

Console.WriteLine(Evaluate("9 + 5"));

Answer 2

You can easily do this with the "Compute" method of the DataTable class.

static Double Eval(String expression)
{
    System.Data.DataTable table = new System.Data.DataTable();
    return Convert.ToDouble(table.Compute(expression, String.Empty));
}

Pass a term in form of a string to the function in order to get the result.

Double result = Eval("7 * 6");
result = Eval("17 + 4");
...