8.1 Programming concepts

By the end of this section you should be able to

• 8.1.1 Declare and use variables and constants
• 8.1.2 Use integer, real, char, string and Boolean data types
• 8.1.3 Use sequence, selection and iteration
• 8.1.4 Use totalling, counting and string handling
• 8.1.5 Use arithmetic, relational and logical operators
• 8.1.6 Write procedures and functions with parameters
• 8.1.7 Use local and global variables and library routines
• 8.1.8 Write maintainable programs

Lessons

1. Variables, constants and data types
2. Sequence, input, output and operators
3. Selection: IF and CASE
4. Iteration: FOR, WHILE and REPEAT
5. String handling and library routines
6. Validation in code
7. Maintainable programs, procedures and functions

Key vocabulary

Variable

A named store whose value can change while the program runs.

Constant

A named value that does not change while the program runs.

Selection

Choosing which code to run based on a condition, using IF or CASE.

Iteration

Repeating a section of code, using a loop.

Count-controlled loop

A FOR loop that repeats a set number of times.

Pre-condition loop

A WHILE loop that tests its condition before each repeat.

Post-condition loop

A REPEAT…UNTIL loop that runs at least once and tests its condition at the end.

Procedure

A named block of code that performs a task and does not return a value.

Function

A named block of code that returns a single value.

Parameter

A value passed into a procedure or function.

Local variable

A variable that can only be used inside the subroutine where it is declared.

Global variable

A variable that can be used anywhere in the program.