Determine if the mailbox format is correct

/Practice: Determine if the mailbox format is correct
1. There is only one @ contains @ indexof @=lastindexof
2. Cannot start with @ indexof! = 0
There is at least one after [email protected].
[email protected] and. Can't stay together.
5. Cannot end with.

Console.Write ("Please enter your e-mail address:"); strings =Console.ReadLine (); if(S.contains ("@")==true)//does it contain @            {                if(S.indexof ("@") !=0&&s.indexof ("@") ==s.lastindexof ("@") )//@ is not the beginning, only one @                {                    stringSS = S.substring (S.indexof ("@"));//intercept the string at the beginning of @                    if(SS. Contains (".")==true)//characters that contain.                    {                        if(SS. IndexOf (".")！ =1&&ss. EndsWith (".")==false)//@ Heel. Do not stay together, and do not end with.{Console.WriteLine ("the mailbox you entered is in the correct format! "); }                        Else{Console.WriteLine ("the mailbox you entered is not formatted correctly"); }                    }                    Else{Console.WriteLine ("the mailbox you entered is not in the correct format! "); }                }                Else{Console.WriteLine ("the mailbox you entered is not formatted correctly"); }            }            Else{Console.WriteLine ("the mailbox you entered is not formatted correctly"); }

The second Kind

Console.Write ("Please enter your e-mail address:"); strings =Console.ReadLine (); BOOLx = S.contains ("@");//determine if there is a @ in the input character            intA = S.indexof ("@");//define first occurrence @ index number a            intb = S.lastindexof ("@");//define last occurrence @ index number B            stringSS = S.substring (a);//intercept the string at the beginning of @            BOOLy = ss. Contains (".");//determine if the SS contains.            intc = ss. IndexOf (".");//appears. Index number of the first time            BOOLz = ss. EndsWith (".");//Judging the end is not.            if(x = =true&& A = = b && y = =true&& C >1&& Z = =false) {Console.WriteLine ("the mailbox you entered is in the correct format! "); }            Else{Console.WriteLine ("The format of the mailbox you entered is incorrect! "); }

Determine if the mailbox format is correct