CS 111 w20 lecture 22 outline

1 binary

base 10 vs base 2
what is a bit?
- How many bits would be need to represent the numbers 0 to 63?
- images we've been working with have been 24-bit (8 bits for each color channel)
  - How many values do we get with 8 bits?
  - all together, 16,777,216 colors
  - progression on wiki article https://en.wikipedia.org/wiki/Color_depth
practice conversions:
- 9 and 42 to binary
- 00111010 and 01000011 to decimal
- add 00001001 and 00001110

base 16
- since a single digit in base 16 can be any number between 0 and 15 in base 10, we need new symbols for the numbers beyond 9
- a, b, c, d, e, f are used for 10, 11, 12, 13, 14, and 15, respectively
how many bits per hexadecimal digit?
you often see colors written in hexadecimal, with two digits for each color (8 bits)
- still in RGB order
- ff0000 is max red, no green or blue
practice arithmetic