PHPz2017-04-18 10:11:47
Brother, your formal parameter name list has the same name as the built-in type list. So the list at this time is no longer a list class. It is a local variable name.
巴扎黑2017-04-18 10:11:47
Rename the list in your function, because list
is a built-in variable and a reference to the list type