使用循环 c# 求和整数

Question

I am new to programming and I think I have confused myself I'm trying to make a loop that asks users for integers when the user inputs a integer greater than 100 then the console displays the amount of integers the user has input and the sum of these integers. I know it's basic but I can't figure where I went wrong.

namespace Wip
{
    class Program
    {
        static void Main(string[] args)
        {
            string strNum1, strNum2;
            int num1, num2;
            int i = 0;
            int sum =0 ;              

            Console.WriteLine("Please enter a integer between 1 and 100"); // asks for user input
            strNum1 = Console.ReadLine();
            num1 = int.Parse(strNum1);

            do //repeat asking for user input
            {
                Console.WriteLine("Please enter another integer between 1 and 100"); // asks for user input
                strNum2 = Console.ReadLine();
                num2 = int.Parse(strNum2); //input is stored as num2
                sum = num2; //store num2 in sum
                i++; 
                if (num2 >= 100) // if num2 int is greater than 100
                {
                    sum = (num1 +num2  +sum); // do calculation
                    Console.WriteLine("No of integers entered is {0} {1}", i, sum); //output calculation 
                }
            }
            while (i < 100);
        }
    }
}

any help would be appreciated thanks everyone!

Answer 1

You're on the right track... a couple of things:

Do... While is used when you always want to run through the block at least once, so your first 'get' from the user can be inside the block. You can code whatever you want to happen after the condition fails right after the block, instead of checking the same condition inside it.

Make sure if you're simply using Parse that you wrap it in a try...catch , because your user could type in anything (not just numbers). Personally I usually use TryParse instead.

Finally, make sure you're comparing to the correct variable. Checking that i < 100 will keep looping until 100 numbers have been entered; you want to compare the user's input instead.

namespace Wip
{
    class Program
    {
        static void Main(string[] args)
        {
            string prompt = "Please enter {0} integer between 1 and 100";
            string strNum;
            int num = 0;
            int i = 0;
            int sum =0 ;              

            do //ask once and repeat while 'while' condition is true
            {
                string pluralPrompt = i > 0 ? "another" : "an";
                prompt = string.Format(prompt,pluralPrompt);
                Console.WriteLine(prompt); // asks for user input
                strNum = Console.ReadLine();
                if (!Int32.TryParse(strNum, out num)) //input is stored as num
                {
                    // warn the user, throw an exception, etc.
                }

                sum += num; //add num to sum
                i++; 

            }
            while (num < 100);

            Console.WriteLine("No of integers entered is {0} {1}", i, sum); //output calculation 

        }
    }
}

Answer 2

namespace Wip
{
    class Program
    {
        static void Main(string[] args)
        {
            string strNum;
            int num;
            int i = 0;
            int sum = 0;

            do //repeat asking for user input
            {
                Console.WriteLine("Please enter another integer between 1 and 100"); // asks for user input
                strNum = Console.ReadLine();
                if (int.TryParse(strNum, out num)) //input is stored as num2
                {
                    if (num < 101) 
                    {
                        i++;


     sum += num;
                    continue;
                }
                else
                {
                    Console.WriteLine("No of integers entered is {0} {1}", i, sum); //output calculation 
                        break;
                    }
                }
            }
            while (i < 100);

    }
}