2.2 - Programming Techniques

2.2 - Programming Techniques

1. Variables

   • Should not contain spaces and they shouldn't start with a number.
   • If the inputs come from the console, from a file or from elsewhere in a modular program.
     • AKA parameters.
   • Booleans
     • And, or, not, larger, smaller, equal, not equal.
   • String/characters
     • Slicing, length, format.
   • Modular division
     • Finding a remainder.
     • 5MOD2 would give 5.
   • Integer division
     • 5DIV2 would give 2
   • Stores values whilst a program is running.
   • Values can change.

2. String Features

   • Slicing
     • LEFT("Monkey") gives "Monk"
   • Length
     • LEN("Monkey") gives 6
   • Change case
     • Monkey ---> MONKEY ---> monkey

3. Sequencing

   • Allows a programmer to solve complex tasks through a number of simple steps.
   • Benefits
     • Each line follows the next.
     • Creates simple programs very quickly.
     • Easy to follow for a small program.
     • Fundamental principals of a program.
       • Starts at the top, finishes at the bottom.
   • Disadvantages
     • Not at all efficient.
     • Becomes very difficult to follow with large programs.
     • Extremely hard to maintain.

4. Selection

   • Changes the flow of a program, depending on a set of decisions.
   • Used for validation, calculation and making sense of a user's choices.
   • Nested Selection
     • A statement within a statement.

5. Constants

   • Store values whilst program is running.
   • Values remain the same.

6. Basic Programming Constructs

   • Sequence
   • Selection
   • Iteration

7. 2 dimensional array

   • Has rows and columns.
   • Each row/column/index holds data.

8. Features of a table

   • Fieldname
     • Title of each column.
   • Primary Key
     • A unique number to identify an object.
   • Record
     • Each individual cell's data.

9. Subroutines

   • Can be repeated in different parts of code.
   • Work can be split between programmers.
   • Functions return a value.
   • Procedures DO NOT return a value.