I have some newbie questions, but I can't easily search for those operators using google therefore hope somebody can help me with.
1. What is the operator :: used for?
It's the scope resolution operator.
2. Is there a different between "" and '' for string
Yes. Double quotes allow interpolation and special characters such as \n. Single quotes don't treat the string special.
3. I saw \exception, what is \ used for?
\ is the namespace operator.
1.Sometimes it is useful to refer to functions and variables in base classes or to refer to functions in classes that have not yet any instances. The :: operator is being used for this.
Refer:http://php.net/manual/en/keyword.paamayim-nekudotayim.php
2.
Single quoted
The simplest way to specify a string is to enclose it in single quotes (the character ').
Double quoted
If the string is enclosed in double-quotes ("), PHP will interpret more escape sequences for special characters.
Refer:http://php.net/manual/en/language.types.string.php
3.Answer is here Importing classes and namespaces in PHP: What difference does a leading backslash make?
