Unit 2.2 - Programming Techniques

Unit 2.2 - Programming Techniques

1. Sequencing

   • Allows a programmer to solve complex tasks through a number of simple steps
   • Each line follows the next
   • Creates simple programs very quickly
   • Easy to follow for a small program
   • Fundamental principal of a program
   • Not efficient
   • Becomes very difficult to follow with large programs
   • Hard to maintain

2. Selection

   • Allows a computer to make decisions
   • Changes the flow of a program depending on a set conditions
   • Used for validation, calculation and making sense of a user's choice
   • Nested Selection
     • Only evaluates a condition if pre-conditions are met
     • There is no limit on how many selection statements we can nest
     • The outside selection is the pre-condition and the inside is the condition

3. An array up to 2D to a file

   • Iterate through an array using WRITELINE and writing elements to the file one by one
   • Serialise the array (convert to a string) using delimiters e.g. commas for columns and NewLines for rows in case of a 2D array
   • Uses numeric index not names
   • Array: An ordered collection of related data where each element is accessible by a number index

4. SQL (Standard Query Language)

   • A popular readable programming language
   • Used to work with databases stored in binary proprietary formats e.g. Oracle, MySQL
   • Purpose of SQL S-Search C-Create R-Read U-Update D-Delete
   • SELECT, FROM, WHERE

5. Variables

   • A "variable" is a memory location that changes throughout the program
   • A "constant" is a memory location that is fixed for the duration of the program
   • "Assignment" is labelling various inputs, constants and outputs with descriptive names
   • Information is stored in memory locations under descriptive names called "identifiers"
   • "Concatenation" is joining inputs/text variables together
   • "Parameters" are inputs coming from the console, from a file or from elsewhere in a modular program

6. Operators

   • Boolean - An outcome of one of two values
   • String - A sequence of characters
   • Concatenate - Join Together
   • Substring - A smaller part of a string
   • Delimiter - One or more characters that separates a string

7. Iteration

   • "Iteration" is when loops run similar types of data
   • A "For Counter" is a loop for when we know how many times we want something to loop so we use a counter
   • "Stepping" is when we skip or miss out when counting
   • A "While Loop" is used for validation and searching. Evaluates a boolean everytime they run