Where to store the number without using any collection like list or array or dictionary or hashtable and ect..?

string s = "1234";int temp = 0;for (int i = 0; i <= s.Length - 1; i++){for (int j = 0; j <= s.Length - 1; j++){if (s[i] > s[j]){temp = s[i];}}}Console.Write(Convert.ToChar(temp));

you can use substring and loop to find number

string a = "517378";int max = 0;while (a.ToString().Length > 1){max = Convert.ToInt32(a.Substring(0, 1));a = a.Substring(1, a.ToString().Length - 1);if (max > Convert.ToInt32(a.Substring(0, 1))){a = a.Remove(0, 1).Insert(0, max.ToString());}}MessageBox.Show("Second Max Num is : "+max.ToString());