Simple judgment of the mailbox format (some of which are not resolved) (see Supplement and hints)

Let the user enter a mailbox and verify the legality of the entered mailbox.

Notes on the legality of the mailbox:

A. There is only one "@" sign.

B. At least one "." After the "@" sign But not more than two.

C. If there are two ".", two "." Can't be together.

D. Cannot start with "@" and cannot end with "@"

E. " @ "and". " Can't be together.

F. Cannot be "." At the beginning, cannot be "." End

Console.Write ("Please enter your e-mail:");

String k = Console.ReadLine ();

int a = K.indexof ("@");

int B = K.lastindexof ("@");

int c = K.indexof (".");

int d = K.lastindexof (".");

BOOL E = K.startswith ("@");

bool F = K.startswith (".");

BOOL G = K.endswith ("@");

bool h = K.endswith (".");

if (A = = B && C > a && c + 1! = d && e = False && F = = False && G = = False &am p;& h = = False)

{

if (c! = d)

{

String L = k.substring (c + 1, d-1);

bool m = L.contains (".");

if (M = = False)

{

Console.WriteLine ("The mailbox is formatted correctly! ");

}

Else

{

Console.WriteLine ("Mailbox format is wrong! ");

}

}

Console.WriteLine ("The mailbox is formatted correctly! ");

}

Else

{

Console.WriteLine ("Mailbox format is wrong! ");

}

Simple judgment of the mailbox format (some of which are not resolved)