Predefined Functions
The following is an uncapitalized sentence:
this is a normal sentence.

After running the 'ucfirst' function:
This is a normal sentence.

User Defined Functions
Menu
Hamburger $3.99
add cheese +$.50
Chicken Sandwich $4.29
Hot Dog $1.99

Explanation
PHP has many built in functions to do various
tasks, and you can also make custom ones. These
are especially useful if you want to repeat an
action many times without retyping code.