1. Lecture Notes 8/24/04 (part 2)

2. Pseudocode (review)
Pseudocode standard which we will follow in this class:
- Statements are written in simple English;
- Each instruction is written on a separate line;
- Each set of instructions is written from top to bottom, with only
one entry and one exit;
- Groups of statements may be formed into modules, and that
group given a name.

3. How to Write Pseudocode
6 basic computer operations:
receive information
put out information
perform arithmetic
assign a value to a variable or memory location
compare two variables and select one of two alternative actions
repeat a group of actions

4. Receive Information
A computer generally gets information in one of the following ways:
From a file
Pseudocode -> “Read”
From a keyboard
Pseudocode -> “Get”

5. Receive Information Examples: Get file name
Read first line from the file
Get number of students
Read the names of the students from the file

6. Put Out Information
A computer generally outputs information in one of the three ways:
Print on a printer
“Print”
Write to a file
“Write”
Display on a monitor
“Display”

7. Put Out Information Examples: Print “Hello everyone!”
Write “My first homework” to hw_1.txt
Display average_age

8. Perform Arithmetic
Either actual mathematical symbols or words can be used:
Multiply Length by Width to compute Area
Area = Length * Width

9. Perform Arithmetic Symbols that will be used in this class:
Addition
Subtraction -
Division /
Multiplication *
Modulus %
Parentheses ()
Also can use the words : Compute and Calculate

10. Example
Write the pseudocode for calculating the average age of the students in our class.
Prompt the user for number of students
Get number of students
Prompt for all of the ages
Get the ages of all students
Add all ages together to obtain Total_Age
Divide Total_Age by the number of students
Display the result