Shulou(Shulou.com)06/01 Report--

The main content of this article is "can C++ use regular expressions?", interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Next, let the editor take you to learn "can C++ use regular expressions?"

The answer must be yes, so today a simple input scanf takes you into the regular world.

# include

Int main ()

{

Printf ("input digate:")

Char str [100]

Scanf ("% [0-9]", str); / / enter 123456abc

Printf ("% s", str); / / print 123456

}

Enter any string of characters that start with a number in scanf, and only the first string of numbers in the character will be saved in str.

Input digate:123456abc

123456

First, give some simple rules.

Qualifier meaning% [0-9] numeric collection% [^ 0-9] non-numeric collection% [a-zA-Z] letter set% [^ a-zA-Z] non-alphanumeric set

Preheat up, let's get down to business.

To determine whether an input QQ number is valid, how to determine?

Judgment steps:

The length is greater than 5, less than or equal to 11; the first bit cannot be 0; is it a pure number? C++string processing: # include

Using namespace std

Int main ()

{

String qq = "7466a2063"

If (qq.length () > = 5 & & qq.length ()

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