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Checking if a Value Exists in a Previously Entered List in C#

This exercise involves creating and searching within a list of floating-point numbers in C#. The program will first ask the user how many numbers they want to enter and store them in an array. Then, the user can repeatedly check whether specific values exist in the list until they decide to end the process. This exercise strengthens skills in arrays, loops, conditional statements, and user input validation.



Group

C# Arrays, Structures and Strings

Objective

1. Ask the user how many numbers they will enter.
2. Reserve space for that many floating-point numbers in an array.
3. Prompt the user to input the numbers and store them in the array.
4. Continuously ask the user for a number and check if it exists in the list.
5. The program should terminate when the user enters "end" instead of a number.
6. The exercise must be done in pairs, but a single source file should be provided, containing both programmers' names in a comment.

Write a C# program that says if a data belongs in a list that was previously created. The steps to take are:
- Ask the user how many data will he enter.
- Reserve space for that amount of numbers (floating point).
- Request the data to the user.
- Later, repeat:
* Ask the user for a number (execution ends when he enters "end" instead of a number).
* Say if that number is listed or not.
Must be done in pairs, but you must provide a single source file, containing the names of both programmers in a comment.

Example C# Exercise

 Copy C# Code 
using System;

class Program
{
    static void Main()
    {
        // Programmers: John Doe & Jane Smith

        Console.Write("How many numbers will you enter? ");
        int count = Convert.ToInt32(Console.ReadLine());

        // Create an array to store floating-point numbers
        float[] numbers = new float[count];

        // Request numbers from the user
        Console.WriteLine("Enter the numbers:");
        for (int i = 0; i < count; i++)
        {
            Console.Write($"Number {i + 1}: ");
            numbers[i] = Convert.ToSingle(Console.ReadLine());
        }

        // Search loop
        while (true)
        {
            Console.Write("\nEnter a number to check (or type 'end' to exit): ");
            string input = Console.ReadLine();

            if (input.ToLower() == "end")
                break;

            if (float.TryParse(input, out float searchNumber))
            {
                // Check if the number exists in the array
                bool found = false;
                foreach (float num in numbers)
                {
                    if (num == searchNumber)
                    {
                        found = true;
                        break;
                    }
                }

                if (found)
                    Console.WriteLine("The number is in the list.");
                else
                    Console.WriteLine("The number is NOT in the list.");
            }
            else
            {
                Console.WriteLine("Invalid input. Please enter a valid number.");
            }
        }

        Console.WriteLine("Program ended.");
    }
}

 Output

How many numbers will you enter? 3
Enter the numbers:
Number 1: 5.5
Number 2: 3.2
Number 3: 8.1

Enter a number to check (or type 'end' to exit): 3.2
The number is in the list.

Enter a number to check (or type 'end' to exit): 7.0
The number is NOT in the list.

Enter a number to check (or type 'end' to exit): end
Program ended.

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More C# Practice Exercises of C# Arrays, Structures and Strings

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