Correct Answer: In this example it wouldn?t matter, since the variable is all by itself, but if you were to print something like "{$a},000,000 mln dollars", then you definitely need to use the braces
5. So if md5( ) generates the most secure hash, why would you ever use the less secure crc32( ) and sha1( )?
Correct Answer: Crypto usage in PHP is simple, but that doesn?t mean it?s free First off, depending on the data that you?re encrypting, you might have reasons to store a 32-bit value in the database instead of the 160-bit value to save on space Second, the more secure the crypto is, the longer is the computation time to deliver the hash value A high volume site might be significantly slowed down, if frequent md5() generation is required
6. What?s the special meaning of __sleep and __wakeup?
Correct Answer: The major difference is the length of the hash generated CRC32 is, evidently, 32 bits, while sha1() returns a 128 bit value, and md5() returns a 160 bit value This is important when avoiding collisions
9. What?s the difference between include and require?
Correct Answer: It?s how they handle failures If the file is not found by require(), it will cause a fatal error and halt the execution of the script If the file is not found by include(), a warning will be issued, but execution will continue