Simpler Is Better
From Huben's Wiki
(Created page with "When we are confronted with a large algebraic expression or lots of ifs, we normally need to slow down and analyze it carefully. Wouldn't it be better if we could write it more ...") |
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</pre> | </pre> | ||
It may seem more difficult to factor out a not (!) using De Morgan's Law: see the homework. | It may seem more difficult to factor out a not (!) using De Morgan's Law: see the homework. | ||
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| + | Why use De Morgan's Law? Sometimes it simplifies the code very nicely. | ||
| + | ==Short Circuit Evaluation== | ||
| + | Sometimes a boolean expression's value can be decided before the whole expression is evaluated. Java exploits this opportunity for optimization. For example: | ||
| + | <pre> | ||
| + | (a !=0 && c == b/a) | ||
| + | </pre> | ||
| + | If a is 0, then the left argument of the && is false, and no matter what the right argument is, the result is false. So Java will not even evaluate the right argument: it will just decide the expression is false. In this example, we use that feature to avoid dividing by zero. If a is not zero, the division will take place. There is a similar short circuit: | ||
| + | <pre> | ||
| + | (a == 0 || c == b/a) | ||
| + | </pre> | ||
| + | Here when the left argument of the || is true, we do not need to evaluate the right argument. | ||
