The underscore before PHP constructor construct is double underline

When I write PHP's class recently, I always encounter the error of function non object, knowing that the class is not instantiated, but I don't know where the error is.

Definition and usage

The construct () function creates a new SimpleXMLElement object.

If successful, the function returns an object. If it fails, it returns false.

Grammar

Construct (Data,options,is_url,ns,is_prefix)

Parameters	Description
Data	Necessary. The path or URL of a well-formed XML string or XML document.
Options	Optional. Specifies the additional Libxml parameters.
Is_url	Optional. Specifies whether the data parameter is a URL. The default is False.
Ns	Optional.
Is_prefix	Optional.

return value

Returns a SimpleXMLElement object that represents the data.

Example

<?php$xmlstring = <<<xml<?xml version= "1.0" encoding= "iso-8859-1"? ><note><to>george </to><from>john</from>
The output is similar to:

Don ' t forget the meeting! later to see construct's former _ is a, I am, last time this error, forget, now remember the function construct () {} is not function _construct () {}