AQA GCSE COMPUTER SCIENCE EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED GRADED A++

AQA GCSE COMPUTER SCIENCE EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED GRADED A++ Terms in this set (123) Data Consists of raw facts and figures without context or meaning. Information What exists when data has been given context or meaning. Variable Space for a single piece of data, each variable has a data type. You can change variables once they have been set. Constant Space for a single piece of data, each constant has a data type. You cannot change constants once they have been set. Boolean A data type, can be either true or false and requires only one bit of storage. Character A data type, a single letter, number, punctuation mark, space etc. - requires one byte. String A data type, stores any number of characters, such as a person's name, address and postcode. Integer A data type, whole numbers, such as a person's age or how much stock a shop has. Real A data type, decimal numbers, such as distances and fractions. Boolean Operator - AND If you see AND between two Boolean expressions, the whole expression is true only if both of the smaller expressions are true. For example: age = 16 AND age = 5 Boolean Operator - OR If either of the expressions either side of the OR is true, then the entire expression is true. Boolean Operator - NOT Adding NOT to an expression simply makes it the opposite of what it was before. For example: NOT (age = 11). This covers all other ages, 12 and up. The meaning of the following operators: = = != = Greater than or equal to Less than = Equal to != Not equal to Array An array is a space in memory reserved for more than one item of the same data type. Two Dimensional Array Table of items and elements, with columns and rows. Data stored in this way can be considered as if it were in a spreadsheet, where each row and each column stands for something. Record Records can combine different data types, and each record would be about one person, or one building or one book. Why we use Data Structures Using data structures instead of lots of individual variables can reduce the amount of code you need to write in order to solve a problem. Arrays also reduce the likelihood of errors occurring, as there are fewer places in the code in which errors could exist. When programs are designed, why are they broken down into smaller tasks and each task is addressed individually? For large programs, different tasks can be assigned to different programmers, with clear understanding of who is to code what. Each component can be tested separately as it is coded, which means the complete program, when all the parts are assembled, will possibly contain fewer errors. If the program needs updating later, the individual component can be updated, leaving the rest of the program unchanged. Why Computer Programs are Written To solve a problem. Algorithm A step-by-step set of instructions to allow a computer to solve a problem in a finite number of steps. Structure Diagrams Shows how a program, or a potential program, is broken down into individual processes.