"<>" not equal (in Python this is written as "!=")
Boolean expressions
A boolean expression evaluates to TRUE or FALSE
Complex Boolean expressions
Boolean expressions can include AND, OR and NOT
AND = Returns TRUE if conditions are true
OR = Returns TRUE if either of the conditions is true
NOT = A TRUE expression becomes FALSE and vice versa
Pseudocode
Pseudocode is a convient way of writing algorithsms without worrying about the syntax of a particular programming language
Testing an algorithm
To make sure your algrotithm works correctly, you should test it with as many sets of test data as needed to make sure it always gives the correct answer
Writing pseudocode
Practice: Write pseudocode for a program which asks the user to enter the cost of two items, adds the two costs and if the cost is greater than $10.00, displays a message "Sorry, too much". Otherwise it displays the change due fro $10.00
Case Statements
A CASE statement is useful if there are are more than two alternative paths through the program
Plenary
IF statements and CASE statements are two different forms of SELECTION statements
IF statements can be "nested"
Some languages such as Python do not have a CASE statement
Pseudocode is a useful tool for developing algorithms before coding them in a programming language
You should use test data to test that your programs always produce the expected results
Testing an algorithm
To make sure your algorithm works correctly, you should test it with as many sets of test data as needed to make sure it always gives the correct answer
Errors often occurs at "boundaries" - eg.a mark of exactly 50 or 70 should be tested