Which is a better composition?

Question

Consider following sentence composed in different ways,

1. And the worst, when memory is full, creation of new node will return a NULL.
2. And the worst is when memory is full and a new node is created because it will return a NULL.
3. And the worst, a NULL is (will be?) returned when memory is full and a new node is created.

The idea is that creating a new node does not return a node but a NULL when memory is full. This might lead to (a) program failure if not handled correctly. To capture this sense, which one of (the) above I should prefer?

Answer 1

Of the three options that you offer, I'd say that #1 is the best. However, I'd suggest this as better yet:

Worst of all, creation of a new node will return NULL when memory is full.

Two things in particular to note:

1. The adjunct clause when memory is full reads best at the end of the sentence. Trying to put it earlier requires that you set it off with commas, which reads awkwardly.
2. Beginning with And the worst is not exactly incorrect, but it is more idiomatic to say Worst of all.