| 1 | <?php  | 
            ||
| 11 | trait Join  | 
            ||
| 12 | { | 
            ||
| 13 | /**  | 
            ||
| 14 | * Join array elements with a string  | 
            ||
| 15 | *  | 
            ||
| 16 | * @param string $glue  | 
            ||
| 17 | *  | 
            ||
| 18 | * @return string Returns a string containing a string representation of all the array elements in the same order,  | 
            ||
| 19 | * with the glue string between each element.  | 
            ||
| 20 | */  | 
            ||
| 21 | 1 | public function join($glue = '')  | 
            |
| 25 | }  | 
            ||
| 26 | 
In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:
Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion: