What does it mean to underline the opening letters

User name alphanumeric underscore means

User name alphanumeric underscore means that the user name must begin with the letters of the alphabet, in addition to the letters can only be used with numbers and underscores. For example: LILY_33453, JUDY12345_ and so on. This means it increases the strength of the password. Generally the most common accounts are QQ, e-mail, blogs, forums and so on.


Username, the name of the account to be logged in or logged on, logged in, entered, that is, in the site where the identification code. You can use Chinese characters, letters, character codes, etc., all as a username.

Generally speaking, any website that allows users to register will have a “Register” tab prominently displayed on its homepage, allowing users to apply.

As long as it meets its requirements, and before any other user has registered the name, the user can register. The most common usernames on the web are QQ, e-mail, blogs, forums, and so on.

What does alphanumeric underlining mean?

This underlining is with buy a remediation portrait meaning

What does alphanumeric underscore mean?

Alphanumeric underscore is the beginning of the user name must be English letters, and in addition to letters can only use numbers and underscores. That is, there can be no Chinese and ¥, %, and other symbols. Underline is pointed out now in the word below a straight line. Underline is generally used in the name of the input, you can only enter numbers, letters, underline and in some documents (such as WORD), underline is often used to enhance the attention. Open the input interface, directly switch the input method to no “American keyboard”, and then use the Word shortcut Shift + “minus” underline how long according to their needs, can be completed.

What does it mean when a username starts with a letter and contains character numbers and underscores?

It means that the username must start with a letter and the username should contain character numbers and underscores.

For example: liu_525823, Mr_Liu111, A_12306, lis_1234, wuhan_1111 and so on.

The username is the identifier of the website you are on. You can use Chinese characters, letters, word code, etc., such as Everest, zmlmf, 12345, etc. are used as the user name. Any site that allows users to register, will be set up on its home page in a prominent position on the “registration” tab, allowing users to apply. If the name has already been registered by someone else, they will be alerted.

Expanded Information

The naming rules of C are:

1. An identifier consists of a letter (A-Z,a-z), a digit (0-9), and an underscore (_), and the first character can’t be a digit, but it can be a letter or an underscore. For example, the correct identifier: abc, a1, prog_to.

2. You can’t use C keywords as user identifiers, such as if, for, while, etc..

3, the length of the identifier is determined by the compilation system on the machine, the general limit of 8 characters (Note: 8 character length limit is the C89 standard, the C99 standard has been expanded length, in fact, most of the industry standards are longer).

What does alphanumeric underscore stand for?

The explanation for alphanumeric underscore is that it can be made up of all three but doesn’t have to be all of them, just numbers or just letters will work, e.g.: abc__123. identifiers are made up of letters (A-Z, a-z), numbers (0-9), underscore “___”, and the first character can’t be a number, but can be a letter or an underscore. For example, the correct identifier: abc, a1, prog_to.

Benefits of alphanumeric underscores:

1. 4-16 characters, consisting of letters, numbers, and underscores Meaning can increase the strength of the password.

2, as long as the length of the password to do within the range of 4-16, can only contain the numbers 0-9, letters a-z, A-Z, and the underscore ___, you can.

3, a lot of websites or applications to register an account are made to limit, first of all, the length of the limit, in principle, the longer the password, the more secure, but not too long.

4. Character limitations, can only be numbers or letters, or the underscore, can not be other, some sites also support other symbols, such as @ # and so on.

5, 4-16 characters within the range of settings have a lot, for example: 168yy_520, AA_789 and so on a lot, as long as they can remember on it.