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Validating c input

Editor's note: We've covered basic data validation techniques and how to evaluate URL encodings in the two previous sample recipes from Secure Programming Cookbook for C and C .This week, the authors cover how to verify the authenticity of an email address.

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Scan the email address supplied by the user, and validate it against the lexical rules set forth in RFC 822. Unfortunately, the syntax is complex, and it supports several address formats that are no longer relevant.It will perform only a syntactical check and will not actually attempt to verify the authenticity of the address by attempting to deliver mail to it or by performing any DNS lookups on the domain name portion of the address.The function only validates the actual email address and will not accept any associated data.For example, it will fail to validate "Bob Bobson TIP: Keep in mind that almost any character is legal in an email address if it is properly quoted, so if you are passing an email address to something that may be sensitive to certain characters or character sequences (such as a command shell), you must be sure to properly escape those characters.Although these flags live in ios_base, because ios is derived from ios_base and ios takes less typing than ios_base, they are generally accessed through ios (eg. ios also provides a number of member functions in order to conveniently access these states: Note that this program is expecting the user to enter an integer.this is a piece of my code, and i declared name as char name [30]; but, it says error argument of type *char is incompatible with parameter type int..

and how to validate if we input randomly alphabet and number together (e.g gghjhj88888)?

Luckily, I was able to parse through the extra characters one-by-one and get something working.

is an undefined behavior, which is better not to involve it in my code in order to prevent any error plus it no longer works in VS2015 due to some reasons.

Data from all potentially untrusted sources should be subject to input validation, including not only Internet-facing web clients but also backend feeds over extranets, from suppliers, partners, vendors or regulators[1], each of which may be compromised on their own and start sending malformed data.

Input Validation should not be used as the primary method of preventing XSS, SQL Injection and other attacks which are covered in respective cheat sheets but can significantly contribute to reducing their impact if implemented properly.

I assume you didn't include an if statement in an if statement, so I don't know what you did there. still has an arbitrary value because you didn't initialize it).