Create Identifiers

题目描述
 Identifier is an important concept in the C programming language. Identifiers provide names for several language elements, such as functions, variables, labels, etc.
An identifier is a sequence of characters. A valid identifier can contain only upper and lower case alphabetic characters, underscore and digits, and must begin with an alphabetic character or an underscore. Given a list of chararcter sequences, write a program to check if they are valid identifiers.
输入
 The first line of the input contains one integer, N, indicating the number of strings in the input. N lines follow, each of which contains at least one and no more than 100 characters. (only upper and lower case alphabetic characters, digits, underscore (" "), hyphen ("-"), period ("."), comma (","), colon (":"), semicolon (";"), exclamation mark ("!"), question mark ("?"), single and double quotation marks, parentheses, white space and square brackets may appear in the character sequences.)
输出
For each of the N lines, output "Yes" (without quote marks) if the character sequence contained in that line make a valid identifier; output "No" (without quote marks) otherwise.
示例输入
7
ValidIdentifier
valid_identifier
valid_identifier
0 invalid identifier
1234567
invalid identifier
adefhklmruvwxyz12356790 -.,:;!?'"()[]ABCDGIJLMQRSTVWXYZ
示例输出
Yes
Yes
Yes
No
No
No
No