编写程序，输入一个正整数，将它的个各位数左右反转输出

Question

例如：123；输出；321。要求对输入的数进行判断，如果输入的数不是正数，就重新输入。然后利用循环输出反转后的数。

Answer 1

            int i = 40212;
            if (i > 0)
            {
                string s = i.ToString();
                System.Char[] l = s.ToCharArray();
                System.Array.Reverse(l);
                s = new string(l);
                i = int.Parse(s);
                MessageBox.Show(s);
            }

Answer 2

        int input = 123456789;
        int output = 0;
        while (input > 0)
        {
            output *= 10;
            output += input % 10;
            input /= 10;
        }
        Console.WriteLine(output.ToString());

Answer 3

void Main()
{
string test = "123";
Console.WriteLine(new string(test.ToCharArray().Reverse().ToArray()));
//321 
}

Answer 4

//C#
private int getReverseValue(int valOrigNumb)
{
    int valOutputNumb = 0;
    while (valOrigNumb > 0)
    {
        valOutputNumb *= 10;
        valOutputNumb += valOrigNumb % 10;
        valOrigNumb /= 10;
    }
    return valOutputNumb;
}

Answer 5

            int num=0;
            do
            {
                Console.WriteLine("请输入一个数");
                string readStr = Console.ReadLine();
                if (int.TryParse(readStr, out num))
                {
                    if (num > 0)
                    {
                        for (int index = readStr.Length - 1; index >= 0; index--)
                        {
                            Console.Write(readStr[index]);
                        }
                    }
                }
            }
            while (num <= 0);
            Console.ReadKey();