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CSharp · Console

/Program.cs

using System;
					
// see: https://stackoverflow.com/questions/13071823/convert-expression-from-a-textbox-to-math-expression-in-code-behind/13071974#13071974
public class Program
{
	public static void Main()
	{
		Console.WriteLine(Eval("15 * (3 + 5) / (7 - 2)"));
	}
	
	public static string Eval(string expr)
	{
		var temp = new System.Data.DataTable();
		string result = null;
		try
		{           
			result = $"{temp.Compute(expr, string.Empty)}"; 
		}
		catch (System.Data.EvaluateException ex)
		{
		  if (ex.Message.ToLower().Contains("cannot find column"))
				throw new System.Data.SyntaxErrorException($"Syntax error: Invalid expression: '{expr}'."
											   + " Variables as operands are not supported.");
		  else
				throw;
		}
    
    	return result;
	}
}