Answer to Question #180519 in C# for Miley

Question

Extension methods on IEnumerable<T>. All of them taking a delegate

1.       CustomAll - Should work as All operation of Linq, with custom logic passed as delegate

2.       CustomAny - Should work as Any operation of Linq, with custom logic passed as delegate

3.       CustomMax - Should work as Max operation of Linq, with custom logic passed as delegate

4.       CustomMin - Should work as Min operation of Linq, with custom logic passed as delegate

5.       CustomWhere - Should work as Where operation of Linq, with custom logic passed as delegate

6.       CustomSelect - Should work as Select operation of Linq, with custom logic passed as delegate

 

Answer 1

using System;
using System.Collections.Generic;
using System.Linq;

namespace Q180519
{
    public static class ExtClass {

        public delegate bool Condition<T> (T n);

        // 1. CustomAll - Should work as All operation of Linq, with custom logic passed as delegate
        public static bool CustomAll<T> (this IEnumerable<T> list, Func<T,bool> condition) {
            return list.All (condition);
        }

        // 2. CustomAny - Should work as Any operation of Linq, with custom logic passed as delegate
        public static bool CustomAny<T> (this IEnumerable<T> list, Func<T,bool> condition) {
            return list.Any (condition);
        }

        // 3. CustomMax - Should work as Max operation of Linq, with custom logic passed as delegate
        public static TResult CustomMax<T,TResult> (this IEnumerable<T> list, Func<T,TResult> function) {            
            return list.Max(function);
        }

        // 4. CustomMin - Should work as Min operation of Linq, with custom logic passed as delegate
        public static TResult CustomMin<T,TResult> (this IEnumerable<T> list, Func<T,TResult> function) {
            return list.Min(function);
        }

        // 5. CustomWhere - Should work as Where operation of Linq, with custom logic passed as delegate
        public static IEnumerable<T> CustomWhere<T> (this IEnumerable<T> list, Func<T,bool> condition) {
            return list.Where (condition);
        }

        // 6. CustomSelect - Should work as Select operation of Linq, with custom logic passed as delegate
        public static IEnumerable<TResult> CustomSelect<T,TResult> (this IEnumerable<T> list, Func<T,TResult> function) {
            return list.Select (function);
        }
    }

    class MainClass
    {
        public static void Print<T> (IEnumerable<T> list) {
            foreach (T el in list)
                Console.Write(el + "  ");
            Console.WriteLine();
        }

        public static void Main (string[] args)
        {
            IEnumerable<int> list = new List<int> () { 3, 2, 1, 2, 3, 4, 5, 4, 3 };

            Console.WriteLine (list.CustomAll(n => n > 0));
            Console.WriteLine (list.CustomAny(n => n == 3));
            Console.WriteLine (list.CustomMax (n => 2 * n));
            Console.WriteLine (list.CustomMin (n => 2 * n));

            IEnumerable<int> whereEnum = list.CustomWhere (n => n % 2 == 1);
            Print (whereEnum);
            IEnumerable<double> selectEnum = list.CustomSelect (n => 0.5 * n);
            Print (selectEnum);
        }
    }
}