Non-terminal Expression (Add):?

Short answer: The Add class represents a non-terminal expression that combines two other expressions (leftExpression and rightExpression). The Interpret method evaluates both sides of the expression and returns their sum. public class Add : IExpression

Example code

{
private readonly IExpression _leftExpression;
private readonly IExpression _rightExpression;
public Add(IExpression left, IExpression right)
{
_leftExpression = left;
_rightExpression = right;
}
public int Interpret() => _leftExpression.Interpret() + _rightExpression.Interpret(); }

Real-world example (ShopNest)

Use a GoF pattern in ShopNest only when it removes duplication or makes a change safer—explain the problem it solves in the interview.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.