PHP TutorialsPhp What is
PHP INI TutorialsPhp ini What is
PHP Functions offer a convenient way of running frequently performed operations. In addition to the large number of built-in functions, PHP lets you create your own. The advantages are that you write the code only once, rather than needing to retype it everywhere you need it.
Php function not only speeds up your development time, but also makes your code easier to read and maintain. If there's a problem with the code in your function, you update it in just one place rather than hunting through your entire site. Moreover, functions usually speed up the processing of your pages.
This is User define function name
This part you can write another PHP code
In the sayHi is a user define function .This function will provide output "Hi"