The standard itself has a better example (well, older versions). In C99 it's:

    printf("Eh???/n");

Which is the same as:

    printf("Eh?\n");

I.e. the "??/" supplies the "\" to the "n", making it a "\n". I think it's good that they're gone (they were there to support some ancient non-ASCII systems). But it's worth mentioning that the "horrifying" semantics are there so that these trigraphs combine with <s>digraphs</s> (edit: "escape sequences", see downthread) in this way.

Otherwise you'd just get:

    printf("Eh?\\n");