使用内置的php函数

Question

My friend just give me a challenge, he wanted to test my programing skill. He ask me to build a function that do something.
So I went and built him the function he wanted. When he saw my function he was surprised that in my function I used a number of php built in functions. He said that a good programmer just builds his own functions and the use of built in functions is considered sloppy code. So I told him that php is a scripting language and no mater what the built in functions are faster because they build in the source code in c++, and its difficult to build function like this in a scripting language. What do you think, Is my friend correct in what he says?

Answer 1

No, your friend is wrong. Not just for PHP, but for most any language out there.

As you correctly surmised, built in functions are almost always faster, and reinventing the wheel just introduces more potential problems and security vulnerabilities.