## CIS 22B - Notes for Monday, 10/1

### Announcements and Reminders

• Assignment 1 is due now
• Check attendance sheet
• Online time:  Tuesday 7:00-8:15 pm ConferZoom Web Page
• Class TA, Fawzan Khan, is available Tuesday and Thursday 11:30 - 3:45 in the ATC lab

• Use of variable length arrays
• What the + or - means
• Excessive inclusion of header files
• Watch variable initialization (especially on a Mac)
• Turn on all warnings on your compiler

### Arrays

#### What is an array?

one variable, multiple parts, contiguous memory
pass entire array to a function
traverse an array
sort, search it

#### How to ...

• Declaration
How big is an array?
Initialization
• Indexing
Segmentation fault
• Traversing an array
Using a for loop
•  Passing an array to a function
How big is an array?
Example
Passing an array as a const
• Passing an array element to a function
Swapping array elements

#### Examples

1. Calculate the sum of an array
2. Calculate the average of an array
3. Calculate the maximum of an array

Videos

### Lab Exercise #2

Put your name, the compiler used, and Lab Exercise #2 in a comment at the top of your program. Email only your source code.

The file below contains first and last names and the radii of circles.  You'll need to cut and paste the data into a text file.  Write a program to read the file and store the first names and the radii in two arrays.  You'll need an array of type string and an another array of some numeric type.  The arrays should each hold 12 elements.  Then, print out the first names and the circle areas, each in a column of width 11.  Make sure you match the implied output format and that you check for a successful file open.  Include a function to calculate of the circle area, using the formula:

Circumference = 2 * PI * radius

For PI, use a named constant equal to 3.1416

Input data - copy to a text file and make sure there is a newline at the end of the last line in the file.

 LoriBeth Allen      79Chachi Arcola      125 Richie Cunningham  171 Howard Cunningham  255 Marion Cunningham  252 Joanie Cunningham  234 Al Delvecchio      122 Arthur Fonzarelli  255 Ralph Malph        165Roger Phillips      61Jenny Piccalo       55 Potsie Weber       210

Program Output

 LoriBeth      19606.73Chachi        49087.50Richie        91863.53Howard       204282.54Marion       199504.17Joanie       172021.45Al            46759.57...