Problem:
n! means n × (n − 1) × ... × 3 × 2 × 1 For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800, and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27. Find the sum of the digits in the number 100! My Solution:
Note: You can simplifies the coding :)
n! means n × (n − 1) × ... × 3 × 2 × 1 For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800, and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27. Find the sum of the digits in the number 100! My Solution:
static void Main(string[] args) { BigInteger multi = 1; long result = 0; int digits = 100; for (int i = digits; i >= 1; i--) { multi *= i; } foreach (var item in multi.ToString().ToCharArray()) { result += long.Parse(item.ToString()); } Console.WriteLine(result); Console.ReadLine(); }
Note: You can simplifies the coding :)
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