F452 Writing maintainable programs.

1. Define the following terms:

• Variable [1]
• Constant [1]
• Reserved word [1]

A variable is a named area of memory of a specific data type that can be changed during the running of the program.

A constant is a named area of memory of a specific data type that doesn't change during the running of the program.

A reserved word is an example of a bad identifier name, they are pre existing words in a programming language.

2. Discuss the need for good programing techniques to facilitate the on going maintenance of programs.  [8]

• Easily understandable identifier names and comments.
• Appropriately positioned scopes for constants and variables.
• Consistent/ meaningful identifiers.
• Well laid out, eg comments, separated blocks.
• To help others understand your code.
• To help others build on your code.
• Functional decomposition (self containing parts of the code by 'encapsulating' them).