A comment that includes the words TODO, FIXME or similar words often indicates code that is incomplete or broken, or highlights ambiguities in the software's specification.

Address the problem indicated by the comment.

In the following example, the programmer has not yet implemented the correct behavior for the case where parameter a is zero: the function will return Infinity or NaN (depending on the values of b and c) in this case.

As a first step to fixing this problem, a check could be introduced that compares a to zero and throws an exception if this is the case. A better solution would be to use a different formula that does not rely on a being non-zero. Regardless of the solution adopted, the TODO comment should then be removed.

Approxion: TODO or not TODO.

Wikipedia: Comment tags.