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• Character


  A letter, number or symbol on a given character set
• String


  A sequence of characters
• Casting


  Changing the data type of a variable
• Count-controlled loop


  A loop that repeats a specific number of times (FOR loops)
• Condition controlled loop


  A loop that runs until a condition is met (WHILE loops)
• Variable


  A value that might need to change while the program is running
• Constant


  A value that would not need to change while the program is running
• Constants


  • Improve readability and are easier to update
• Subprogram


  A block of code that performs a specific task
• Libraries


  Collections of pre-written subprograms for specific purposes
• Local variable


  A variable that is declared inside a function or procedure so can be accessed within the subprogram
• Global variable


  A variable that can be accessed from anywhere
• Functions return a value
• Procedures do not return a value
• Array


  A data structure with one or more elements of the same type (have a fixed length only contain elements of the same data type)
• Index


  A position within an array
• 1D array


  An array that stores data in one direction (horizontal)
• 2D array


  An array that stores data horizontally and vertically (indexed with two numbers)
• It is good to close files after use as it frees up resources, prevents corruption and flushes the buffer
• MOD


  Gives remainder
• DIV


  Shows how many times x goes into y (23 DIV 5 = 4)
• Boolean operator NOT


  The opposite of the input
• Boolean operator OR


  If one side is true then the output is true
• Boolean operator AND


  Both sides have to be true for the output to be true
• Iterative testing


  Testing in stages
• Final testing


  Testing after implementation
• Sanitisation


  Modifying an input to make it valid
• Overflow error


  An error that occurs because a value is too large for the program to handle
• Bitmap


  An image stored as an array of individual pixels
• Pixel


  An individual picture element
• Resolution


  The amount of detail an image holds
• The equation for size of image is Width * Height
• Colour depth


  The number of bits allocated to represent each pixel's colour
• Increasing resolution and colour depth


  Gives a greater quality image but increases file size
• The equation for File size is File size = Width * Height * Colour depth. File size is measured in bits, Width and Height are measured in pixels, Colour depth is measured in bits.
• Metadata


  Includes file name, file format, colour depth, resolution
• Increasing bitrate


  Causes more detailed audio but more storage required
• Sampling


  Recording a signal at regular intervals
• Sampling frequency


  The number of samples obtained per second (Hz)
• Increasing sampling frequency


  Gives a truer digital signal to the original but a greater file size