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求助这道C#的loop题目要怎么写

来源:学生作业帮 编辑:作业帮 分类:综合作业 时间:2024/05/29 11:21:57
求助这道C#的loop题目要怎么写
Write a C# program to find the factorial of a number. You are required to
• Accept a positive integer number from the user at run time (2 Marks)
• Use exception handling technique to avoid format problems (5 Marks)
• Use loops (3 Marks)
You are free to use recursion technique or simple method or property. (5 Marks)
static void Main(string[] args)
        {
            ulong input = 0;
            while (input<=0 || input>65)
            {
                Console.WriteLine();
                Console.Write("input a number between 0 and 65:");
                try
                {
                    input = ulong.Parse(Console.ReadLine());
                    if (input > 65) throw new Exception();
                }
                catch
                {
                    Console.WriteLine("error format! input again.");
                }
            }
            Console.WriteLine("factorial of {0} is {1}.", input, fact(input));
            Console.ReadKey();
        }
        static ulong fact(ulong i)
        {
            if (i <= 1) return 1;
            return fact(i - 1)*i;
        }