using System;

namespace LambdaExpressionExample
{
    class Program
    {
        static void Main(string[] args)
        {
            Func<int, int, int> addFunction = (a, b) => a + b;
            Func<int, int, int> multiplyFunction = (a, b) => a * b;

            Func<int, int, int> ChooseFunction(string operation)
            {
                return operation switch
                {
                    "add" => addFunction,
                    "multiply" => multiplyFunction,
                    _ => throw new ArgumentException("Invalid operation"),
                };
            }

            var selectedFunction = ChooseFunction("add");
            Console.WriteLine(selectedFunction(3, 4)); // Output: 7
        }
    }
}