As you continue to develop your skills in modular thinking and method design, it is time to put these concepts into practice by building a mini algorithm library. This challenge will reinforce your understanding of **pure functions**, **stepwise decomposition**, and the value of organizing code into reusable components. By creating a set of methods that each solve a specific algorithmic task, you will see firsthand how modular code is easier to read, test, and maintain.


using Xunit;
namespace ConsoleApp {
    public class ProgramTests {
        [Fact(DisplayName = "FindMax returns the largest value in the array (distinct values)")]
        public void FindMax_ReturnsLargestValue_Distinct()
        {
            int[] arr = { 1, 9, 3, 7, 5 };
            Assert.Equal(9, Program.FindMax(arr));
        }

        [Fact(DisplayName = "FindMin returns the smallest value in the array (distinct values)")]
        public void FindMin_ReturnsSmallestValue_Distinct()
        {
            int[] arr = { 1, 9, 3, 7, 5 };
            Assert.Equal(1, Program.FindMin(arr));
        }

        [Fact(DisplayName = "ReverseArray returns a new array with elements in reverse order")]
        public void ReverseArray_ReturnsReversedArray()
        {
            int[] arr = { 10, 20, 30, 40 };
            int[] expected = { 40, 30, 20, 10 };
            Assert.Equal(expected, Program.ReverseArray(arr));
        }

        [Fact(DisplayName = "FindMax handles single element array")]
        public void FindMax_SingleElement()
        {
            int[] arr = { 42 };
            Assert.Equal(42, Program.FindMax(arr));
        }

        [Fact(DisplayName = "FindMin handles single element array")]
        public void FindMin_SingleElement()
        {
            int[] arr = { -5 };
            Assert.Equal(-5, Program.FindMin(arr));
        }

        [Fact(DisplayName = "ReverseArray handles single element array")]
        public void ReverseArray_SingleElement()
        {
            int[] arr = { 99 };
            int[] expected = { 99 };
            Assert.Equal(expected, Program.ReverseArray(arr));
        }

        [Fact(DisplayName = "FindMax handles array with all equal elements")]
        public void FindMax_AllEqual()
        {
            int[] arr = { 3, 3, 3, 3 };
            Assert.Equal(3, Program.FindMax(arr));
        }

        [Fact(DisplayName = "FindMin handles array with all equal elements")]
        public void FindMin_AllEqual()
        {
            int[] arr = { -2, -2, -2, -2 };
            Assert.Equal(-2, Program.FindMin(arr));
        }

        [Fact(DisplayName = "ReverseArray handles array with all equal elements")]
        public void ReverseArray_AllEqual()
        {
            int[] arr = { 7, 7, 7 };
            int[] expected = { 7, 7, 7 };
            Assert.Equal(expected, Program.ReverseArray(arr));
        }
    }
}

ProgramTests.cs

Master the art of writing modular, reusable, and clear code in C# by learning how to create, use, and reason about methods. This course guides you from the basics of function signatures to advanced modularization techniques, with engaging real-world challenges and step-by-step explanations.

Explore the fundamentals of C# methods, including defining, calling, and understanding different parameter and return types. Practice writing and using methods with a variety of signatures.

Learn how to write methods that return arrays, and how to refactor repetitive loops into reusable functions for cleaner code.

Explore the concepts of pure and impure functions, and learn how to break down complex problems into smaller, manageable methods using stepwise decomposition.

Challenge: Mini Algorithm Library

Solution

Challenge: Mini Algorithm Library

Solution