add all numbers though entered number and displaysa it .txt

  
        //declaration 
        int sum = 0;
        int userInput; 

        Console.Write("Enter a number: "); // Prompt user for input

        userInput = Convert.ToInt32(Console.ReadLine()); // Reading user input as an integer

        sum = 0; // Initializing a variable to store the sum

        // Loop to calculate the sum of numbers from 1 to 'n'
        for (int i = 1; i <= userInput; i++)
        {
            sum += i; // Adding each number to the sum
        }

        // Displaying the sum of numbers from 1 to the entered number
        Console.WriteLine("The sum of numbers from 1 to {0} is: {1}", userInput, sum);