Something thatâ?Ts used in an expression to manipulate objects such as + (plus), - (minus), * (multiply), and / (divide). You can also use operators to do comparisons,such as with <, >, and &&.

To use figures of speech such as metaphors -- comparisons of two things that don't use like or as -- it definitely helps to have examples. The trick with using metaphors is to watch out for cliches and avoid mixing them. Expressions like "the calm before the storm," "Mother Nature," or "he's a rat," have been used so often that they're now cliches. Although it's difficult to avoid cliches altogether, make an effort to either use more original metaphors, or simply choose straightforward description.

Another common problem with regard to metaphors is the tendency to mix them or overwork them, usually from careless thinking, as in the example above, or over thinking.

Hashing is that some data either has no inherent ordering (such as images) or is expensive to compare (such as images). If the data has no inherent ordering, you can't perform comparison searches.
If the data is expensive to compare, the number of comparisons used even by a binary search might be too many. So instead of looking at the data themselves, you condense (hash) the data to an integer (its hash value) and keep all the data with the same hash value in the same place. This task is carried out by using the hash value as an index into an array.