Page 1231 - AP Computer Science A, 7th edition

21. (B) The postcondition should be a true assertion about the major action of the segment. The segment overwrites the elements of array a with the nonnegative elements of a. Then n is adjusted so that now the array a[0]...a[n–1] contains just nonnegative integers. Note that even though choice E is a correct assertion about the program segment, it is not a good postcondition because it doesn’t describe the main modification to array a (namely all negative integers have been removed).