Chapter 7 - Programming Flashcards
Algorithms
Sets of rules that define a solution to a problem
Pseudocode
A structured form of English used to define the steps needed to solve a problem
Machine code
A stream of binary code that represent instructions that are to be carried out - specific to computer
Low-level code
Works at the level of computer hardware
Assembly language
Uses mnemonics to represent instructions
High-level languages
Commands may represent several machine code instructions
Compiler
Converts whole code into machine code before running it. Source code runs independently to object code so compiler not needed and difficult to modify
IDE
Integrated development environment includes source code editors, debuggers etc
Sequence
The path through a program that the computer follows in order
Selection
Path through program decided by condition
Iteration
Set of instructions repeated several times
Variable
A named storage reserved in memory for data to be used in a program. It can be updated by the program and has no value at design time
Constant
A place reserved in memory for data to be used in a program. It cannot be changed by the program, only at the editing stage
Array
A set of variables with the same name and an index number to identify the different variables
Syntax errors
Errors in the use of language rules e.g. undeclared variables
Logical errors
Errors as a result of flawed logic e.g. infinite loops. Error does not prevent the program running but does not produce expected output
Why can testing never be complete? (4)
1) Complex software
2) Expensive
3) Time consuming
4) Lots of pathways
Where are binary bit patterns of low-level code decoded?
Processor’s logic circuits
Why is writing programs in machine code difficult and time consuming? (2)
1) Each operation has to be defined
2) Each instruction is just one operation
What is the operator/ opcode?
Instruction - tells processor what to do
What is the operand?
Data part of instruction
What is an assembler?
Software that converts mnemonics from assembly code to machine code - precise and direct but difficult to code and limited commands
What does an interpreter do?
Converts high-level code one instruction at a time, running each before translating the next. Source code is needed to run program so code will run on any machine but slower and easy to modify
What can an IDE include? (4)
1) Source code editor - easier to code - more accurate
2) Debugger - less errors + time on improving
3) Translator
4) Autocomplete code - save time
What can happen with logical errors? (3)
1) Programs do not complete
2) Memory filled
3) Incorrect output
Why do we need testing?
To discover errors and ensure software conforms to specifications
What is the size of a string, integer, real and boolean variable?
String - 5 bytes
Integer - 2-4 bytes
Real - 4-8 bytes
Boolean - 1 bit
