public static void Main(string[] args)
{
Context context = new Context();
// define set of variables
Complex x = new Complex(15, 9);
Complex y = new Complex(5, 3);
// add variables to context
context.SetVariable("x", x);
context.SetVariable("y", y);
// Object to calcute sum
IExpression additionExpression = new AddExpression(new NumberExpresssion("x"), new NumberExpresssion("y"));
Complex sum = additionExpression.Interpret(context);
Console.WriteLine(sum);
// Object to calcute difference
IExpression substractionExpression = new SubtractExpression(new NumberExpresssion("x"), new NumberExpresssion("y"));
Complex difference = substractionExpression.Interpret(context);
Console.WriteLine(difference);
// Object to calculate product
IExpression multiplicationExpression = new MultiplyExpression(new NumberExpresssion("x"), new NumberExpresssion("y"));
Complex product = multiplicationExpression.Interpret(context);
Console.WriteLine(product);
// Object to calculate quotient
IExpression divisionExpression = new DivideExspression(new NumberExpresssion("x"), new NumberExpresssion("y"));
Complex quotient = divisionExpression.Interpret(context);
Console.WriteLine(quotient);
Console.Read();
}