AP Computer Science Principles EXAM Questions & Answers
Overflow - ans-error that results when the number of bits is not enough to hold the number, like a car's
odometer "rolling over"
Round-off - ans-error that results when the number of bits is not enough to represent the actual
number, like 3 digits to represent π as 3.14
Lossy - ans-Compressing data in a way that throws some data away and makes it almost impossible to
recover the original, great compression, like JPEG images
Lossless - ans-Compressing data in a way that preserves all data away and allows full recovery of the
original, good compression -- usually not as good as lossy, like PNG images
Metadata - ans-data about data, like a camera storing the location, aperture, shutter speed, etc. for a
digital photo
Sequencing - ans-code flows line by line, one after another, like a recipe
Selection - ans-a boolean condition to determine which of two algorithmic paths are taken, aka if-then
Iteration - ans-using a looping control structure, like while, for, foreach, repeat, repeat-until, etc.
Reasonable Time - ans-polynomial in the number of steps an algorithm takes in the worst case based on
the input size
Not reasonable time - ans-Usually exponential in the number of steps, like doubling every time your
input grows by one
Heuristic - ans-using a "rule" to guide an algorithm, like always walking toward the north star if you were
stuck in a forest
Undecidable - ans-A problem that is so difficult, we can't ever create an algorithm that would be able to
answer yes or no for all inputs, like determining if a user's program run on some input would always
stop and not run forever