# CIS-180 Homework #1

## Due: Wednesday, September 14

### Software Lifecycle (5 points)

- What are the major phases of the software lifecycle? Give a
brief (one or two sentence) description of each phase, and indicate the
relative cost of each phase in a typical large scale software
development project.

### Binary Representation of Data (5 points)

- Give the binary representation of each of the following
decimal numbers: 37, 74, 135, 270.
- In the decimal system, a number that is a multiple of 10
ends with a 0, and adding a zero at the end multiplies a number by 10.
What does it mean if a binary number ends with a 0? What happens if you
add a zero to the end of a binary number?
- Suppose we want to encode messages that consist only of
upper case letters, spaces, and periods. How many bits do we need to
encode each character?
- Suppose we want to store a binary value to indicate the
style attributes of some text. The style attributes are bold, italic,
and underline. These three attributes can be applied to text
in any combination. How many bits are needed to represent the style?
- How many distinct values can be represented using n bits?