Programming basics

Features that make code understandable

• Indentation

• White space

• Comments

• Meaningful variable names

• Capitalised keywords

Importance of good practice

• Makes code easier to understand, describes purpose of sections of code and of identifiers

• Makes code easier to debug/test and maintain

Constants

• Used for values that are only entered once

• Avoids input error or accidental change of value

• Easier to maintain program when constant has to change (change once, automatically update)

• Makes program easier to understand

Library routines + benefit during development

• More complex functions can be used in code through use of a program library

• Tried and tested free from errors

• Perform functions programmers may not be able to program themself

• Readily available and speed up development time

Use of library routines

• Used for tasks that are performed/repeated in several places within the code

• When part of an algorithm performs a specific task

• Reduces complexity of program

• Easier testing/debugging

Selection constructs

• IF statement

• CASE statement

  • Consists of clauses that are checked in sequence

  • If a value satisfies the first clause, other clauses will never be tested

  • The “otherwise” clause may never be performed if all possible values are addressed via the other previous clauses

Iterative constructs

• WHILE pre conditional loop - used when number of iterations is not known

• REPEAT post conditional loop - used when number of iterations is not known

• FOR count-controlled loop - used for known number of iterations