Can anyone help me add a captcha program??? 200

Import namespace:

byte b=new byte[100];

random r=new random();

int code;

The verification code generated by a for loop control is 4 digits.

for(int i=0;i<4;i++)

code=,122);

b=;asciiencodeing a=new asciiencodeing;

string ab=,0,4);

return ;

Can't see clearly.

Use this:Import namespace:

byte b=new byte[100];

random r=new random();

int code;

The verification code is made into 4 digits:

for(int i=0;i<4;i++)

code=,122);

b=;asciiencodeing a=new asciiencodeing;

string ab=,0,4);

return ;

Can't see clearly.

Go directly to the source code station and find one.

Here's how:Operating tool: Xiaomi Mi 9

Operating system: MIUI

Procedure: SMS.

The verification code is a string of randomly generated numbers or symbols, and a ** is generally used to prevent batch registration.

1. The role of the verification code is to effectively prevent this problem from constantly logging in attempts to crack a specific program for a specific registered user, in fact, using the verification code is now a common way for many people, such as China Merchants Bank's online personal banking, Tencent's QQ community, and we use a relatively simple way to achieve this function.

2. Although it is a little troublesome to log in, this function is still very necessary and important for the community, but we still remind everyone to protect their passwords, try to use more than 6 digits of passwords mixed with numbers, letters, and symbols, and do not use simple passwords such as 1234 or passwords that are the same or similar to the user name.

3. Don't set a password at will just because you just come to iclub to ask questions, and protecting your own password is also protecting yourself, so as not to cause unnecessary trouble to yourself if you are stolen by others.

4. Common verification code four-digit number, random one-digit string, the most primitive verification code, the verification function is almost zeroCSDN**User login is in GIF format, the current commonly used random number**Captcha, **The characters on the trembling Yumin are more decent, and the verification effect is better than the previous one.

You are asking your captcha here, how do I know that your captcha is in**? Do you see if there is a short message in your SMS record that sends a verification code? Stupid hail to see if there is one? Maybe you've missed the key.

What the captcha does:

Effectively prevent a hacker from making continuous login attempts to brute-force crack a specific registered user with a specific program, in fact, using a verification code is now a common way (such as China Merchants Bank's online personal banking, Tencent's QQ community), we use a relatively simple way to achieve this function. Although it is a little troublesome to log in, this function is still necessary and important for the password security of netizens. But we still do.

Remind everyone to protect their own Michun guessing code.

Try to use a password with more than 6 digits including numbers, letters, and symbols, and do not use a simple password such as 1234 or a password that is the same or similar to your username.

lest you be misappropriated and bring unnecessary trouble to yourself.

1）.Captcha is generally to prevent batch registration, and it looks hard for the human eye to do it, let alone a machine. Two like the post bar is not logged in to post to enter the verification code is probably to prevent the occurrence of large-scale anonymous replies At present, many ** in order to prevent users from using robots to automatically register, log in, and irrigate, all use pure god verification code technology.

The so-called verification code is a string of randomly generated numbers or symbols, generating a **,** add some interference pixels (to prevent OCR), the user recognizes the verification code information by the naked eye, enters the form to submit** verification, and only after successful verification can a certain function be used.

2）.Generally, the place where the user ID is registered and the major forums require a verification code.

3）.Common captchas.

1. Four-digit number, a random one-digit string, the most original verification code, the verification effect is almost zero. 2. CSDN** user login is in GIF format, which is currently commonly used as a random number ** verification code. **The characters on the ** are more decent, and the verification effect is better than the previous one.

For those who do not have basic graphic iconography knowledge, it is unbreakable! It's a pity that the program that reads it, on the first day that csdn used it, seems to have been published in the forum, which is really pitiful!

2. Chinese characters, QQ** registration is currently the latest verification code, all of which are Chinese characters, randomly generated, and it is more difficult to fight!

3,QQ**User login is in png format,**Random numbers + random capital English letters,The whole composition is a bit flamboyant,Every time you refresh it,Each character will change its position! Sometimes the ** that comes out can't be recognized by the human eye, it's amazing....4. When MS hotmail is applied, it is in bmp format, random number + random capital English letters + random interference pixel + random position.

4. Korean or Japanese, now you have to play Korean for MS registration on HF, which increases the difficulty, and you have to go to study.

5, Google's gmail registration is in jpg format, random English letters + random color + random position + random length.

6. Other major forums are in XBM format, and the content is random.