Chapter 7 - Programming

Question 1

Algorithms

Answer 1

Sets of rules that define a solution to a problem

Question 2

Pseudocode

Answer 2

A structured form of English used to define the steps needed to solve a problem

Question 3

Machine code

Answer 3

A stream of binary code that represent instructions that are to be carried out - specific to computer

Question 4

Low-level code

Answer 4

Works at the level of computer hardware

Question 5

Assembly language

Answer 5

Uses mnemonics to represent instructions

Question 6

High-level languages

Answer 6

Commands may represent several machine code instructions

Question 7

Compiler

Answer 7

Converts whole code into machine code before running it. Source code runs independently to object code so compiler not needed and difficult to modify

Question 8

IDE

Answer 8

Integrated development environment includes source code editors, debuggers etc

Question 9

Sequence

Answer 9

The path through a program that the computer follows in order

Question 10

Selection

Answer 10

Path through program decided by condition

Question 11

Iteration

Answer 11

Set of instructions repeated several times

Question 12

Variable

Answer 12

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

Question 13

Constant

Answer 13

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

Question 14

Array

Answer 14

A set of variables with the same name and an index number to identify the different variables

Question 15

Syntax errors

Answer 15

Errors in the use of language rules e.g. undeclared variables

Question 16

Logical errors

Answer 16

Errors as a result of flawed logic e.g. infinite loops. Error does not prevent the program running but does not produce expected output

Question 17

Why can testing never be complete? (4)

Answer 17

1) Complex software
2) Expensive
3) Time consuming
4) Lots of pathways

Question 18

Where are binary bit patterns of low-level code decoded?

Answer 18

Processor’s logic circuits

Question 19

Why is writing programs in machine code difficult and time consuming? (2)

Answer 19

1) Each operation has to be defined

2) Each instruction is just one operation

Question 20

What is the operator/ opcode?

Answer 20

Instruction - tells processor what to do

Question 21

What is the operand?

Answer 21

Data part of instruction

Question 22

What is an assembler?

Answer 22

Software that converts mnemonics from assembly code to machine code - precise and direct but difficult to code and limited commands

Question 23

What does an interpreter do?

Answer 23

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

Question 24

What can an IDE include? (4)

Answer 24

1) Source code editor - easier to code - more accurate
2) Debugger - less errors + time on improving
3) Translator
4) Autocomplete code - save time

Question 25

What can happen with logical errors? (3)

Answer 25

1) Programs do not complete
2) Memory filled
3) Incorrect output

Question 26

Why do we need testing?

Answer 26

To discover errors and ensure software conforms to specifications

Question 27

What is the size of a string, integer, real and boolean variable?

Answer 27

String - 5 bytes
Integer - 2-4 bytes
Real - 4-8 bytes
Boolean - 1 bit