Question

I want to develop a calculator in C#. I have been programming Perl a bit. In Perl, I can use string eval in the following way:

while(<STDIN>) {
    $i = $_; chomp($i); unless($i) { last }
    $o = eval($i); print "$i = $o\n";
}

With this code, I can enter:

1. (2+2+2)*5
2. cos(5)
3. sqrt(4)

It recognizes a lot of different expressions.

I am not very familiar with C# – so my question is:

Can I do something like the above just in C# instead of Perl?

Answer 1

Unfortunately there is not a straight way to do it as in Perl, since C# is a compiled language, it cannot interpret souce code strings on-the-fly.
So, you have at least two alternatives:

• Use an expression evaluator, like the one here: http://flee.codeplex.com or http://ncalc.codeplex.com There are plenty as well in codeproject.com searching for the phrase “expression evaluator”

  • Compile on-the-fly a code snippet and run it, using C# 4.0 dynamic method (http://msdn.microsoft.com/en-us/library/exczf7b9.aspx). Here is a ready-made case: http://www.360doc.com/content/07/0314/20/8309_397508.shtml

Hope this helps