Bitops are an really interesting way to reduce a large selection of bits (or yes/no answers) into a single number. Bit ops use numbers that only allow for one possible way to arrive at the end value. Let me explain that in a different way. If you need to give someone $0.25 in change, you could do it in more than one way. You could give them 1 quarter, or 2 dimes and a nickel, or 25 pennies. There are many ways to get to $.025 With a bit op, this cant happen. a bitop uses numbers starting with: 1,2,4,8,16,32,64,128,256 (See a pattern here?). If you look at the numbers, you will see there is only one way to make 8. same with all the other numbers listed. Because of this, a number can hold many unique combinations of bits. Let's try a few examples. Lets say we have a checklist with 7 check boxes. Below each checkbox is a value I have assigned it:
I can describe the set of checkboxes with a 2 digit number. 41. Another example:
The total is 86. Try to make 86 any other way using each number only once. (Hint: You can't!) This same technique is used to save space in a database. If I had a form with 9 checkboxes, normally I would have 9 fields in the database with 1 digit each (or technically a bit). Instead, I can have 1 field with 3 digits. This technique pops up quite often in electronics, and computer networking. Learn it now. I'm sure you'll see it again! |

FunStuff >