In this challenge, you will apply your understanding of **do-while loops** by simulating a simple number guessing game. The key feature of this task is that the guessing loop must always execute at least once, regardless of whether the guess is correct on the first try. This ensures you gain practical experience using a **do-while loop**, which guarantees the loop body runs before any condition is checked.

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using Xunit;
using System;
using System.IO;

namespace ConsoleApp {
    public class ProgramTests {
        [Fact(DisplayName = "Loop runs at least once even if first guess is correct")]
        public void Loop_ExecutesAtLeastOnce_WhenFirstGuessCorrect() {
            var sw = new StringWriter();
            Console.SetOut(sw);

            Program.RunGuessingGame(5, new int[] { 5 });

            string output = sw.ToString();
            Assert.Contains("You guessed it!", output);
            Assert.Contains("Guessing number: 5", output);
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }

        [Fact(DisplayName = "Loop stops when correct number is guessed or guesses exhausted")]
        public void Loop_StopsOnCorrectGuessOrEndOfGuesses() {
            var sw = new StringWriter();
            Console.SetOut(sw);

            Program.RunGuessingGame(5, new int[] { 2, 3, 5 });

            string output = sw.ToString();
            // Should include two 'Try again.' and one 'You guessed it!'
            Assert.Contains("Try again.", output);
            Assert.Contains("You guessed it!", output);
            int countTryAgain = output.Split(new[]{"Try again."}, StringSplitOptions.None).Length - 1;
            int countCorrect = output.Split(new[]{"You guessed it!"}, StringSplitOptions.None).Length - 1;
            Assert.Equal(2, countTryAgain);
            Assert.Equal(1, countCorrect);
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }

        [Fact(DisplayName = "Program responds correctly to correct and incorrect guesses")]
        public void Program_CorrectlyIdentifiesGuesses() {
            var sw = new StringWriter();
            Console.SetOut(sw);
            Program.RunGuessingGame(5, new int[] { 2, 3, 5 });
            string output = sw.ToString();
            Assert.Contains("Try again.", output);
            Assert.Contains("You guessed it!", output);
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }

        [Fact(DisplayName = "Program outputs correct response for all incorrect guesses")]
        public void Program_HandlesAllIncorrectGuesses() {
            var sw = new StringWriter();
            Console.SetOut(sw);

            Program.RunGuessingGame(10, new int[] { 1, 2, 3 });

            string output = sw.ToString();
            int countTryAgain = output.Split(new[]{"Try again."}, StringSplitOptions.None).Length - 1;
            Assert.Equal(3, countTryAgain);
            Assert.DoesNotContain("You guessed it!", output);
            Assert.Contains("Guessing number: 1", output);
            Assert.Contains("Guessing number: 2", output);
            Assert.Contains("Guessing number: 3", output);
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }
    }
}

ProgramTests.cs

Deepen your understanding of C# loops with a hands-on, challenge-driven course. Explore for, while, and do-while loops, master nested structures, generate patterns, and tackle real-world problems. Each section alternates between engaging theory and practical coding challenges to ensure you build both conceptual understanding and practical fluency.

Explore the full power of for loops in C#, from basic counting to custom steps and real-world data processing.

Master while and do-while loops for scenarios where the number of iterations isn't known in advance, and learn to control loop execution with conditions.

Delve into advanced looping techniques, including nested loops for pattern generation, loop transformations, efficiency, and avoiding common mistakes.

Challenge: Number Guessing Simulation

解答