How to make good use of PHP recursive function return values ​​and return statements? Detailed examples

The return value problem of php recursive function

Example:

There is a problem in else in the above code. The test executed here has no return value. Therefore, although the condition $i

Make the following modifications to the above php recursive function:

Notes on return values ​​in php recursive functions

When using return in a PHP recursive function, you will encounter situations where the desired value cannot be returned correctly. If you don’t understand the reason, it will be difficult to find the error.

Example: