Given an input plaintext, rotate the even-indexed characters (starting with the first character, index 0) into subsequent even positions. A rotation implies that the last character with an even index will become the new first character with index 0. Do this rotation a number of times equal to the length of the plaintext divided by 4 (use integer division). As an example consider the plaintext "012345678" (length 9). This plaintext will cause 2 rotations (9/4 == 2 when leaving aside remainders). After the first rotation it would read as "810325476", after the second rotation "618305274".

HINT

Consider an outer for loop, since this method has to accomplish the rotation task a set number of times. Also note that this method is going to work slightly differently on inputs with odd vs. even lengths.