Generate All Binary Strings

You are asked to create a recursive function to generate all the binary strings of length n.

Binary strings are sequences of 1's and 0's. For example, for n=3, the binary strings are 000, 001, 010, 011, 100, 101, 110, 111.

The input of the program is a single integer n that represents the length of the binary strings.

The output of the program should be all the binary strings of length n each on a new line in no particular order.