Programming

Question 1

What is a variable

Answer 1

Any value that will change unless it’s a constant

Question 2

Variables must be declared with

Answer 2

In python one statement that includes the data type

Question 3

Different data types ares

Answer 3

Integer- whole number 
Boolean- two choices 
Character - symbol on keyboard (single)
String- zero or several symbols 
Float/Real- fractional number

Question 4

Constant variable

Answer 4

A variable that is the same throughout the program

Question 5

Benefits of constant variables are

Answer 5

Easy to debug program

Easy to change value as it only needs to be changed once eg VAT

Question 6

2 types of operations

Answer 6

Arithmetic and comparison do stuff to specific pieces of data

Question 7

Num1=input
Num2=input
Num3=Num1+Num2
prints”the same is “,Num3)

What will happen and why

Answer 7

It’s will join the numbers together (concatenation) because it hasn’t been changed to int

Question 8

Sequence-

Answer 8

Series of steps in specific order

Question 9

Selection

Answer 9

Choice , IF THEN ELSE

Question 10

Nested iteration and selection

Answer 10

A loop within a loop

Choices made within the process of making a choice

Question 11

A robust code is

Answer 11

A code that will not crash and will anticipate unexpected user inputs

Question 12

Arrays

Answer 12

A list with only one data type

Question 13

Benefits of arrays

Answer 13

Easily debugged

Easily processed

Question 14

Iteration

Answer 14

For is definite
While is indefinite
Repeat….until is indefinite

Question 15

Data structure

Answer 15

Grouping data items together so are treated as a set

Question 16

Subroutine

Answer 16

A named self contained section of the code that performs a specific task.
Def()

Question 17

Benefits of subroutines

Answer 17

Makes the program structure easy to read

Each subroutine can be tested separately

Question 18

2 types of subroutine

Answer 18

Procedures and function

Question 19

Procedures

Answer 19

Just carry out instructions nothing is returned

Question 20

Functions

Answer 20

Carry out instructions but always return a statement

Question 21

A global variable is used. Whereas a local variable is

Answer 21

All throughout the program whereas a local variable is is only in a certain part of the program eg subroutine

Question 22

A structured program

Answer 22

Breaks a program into chunks of subroutines which will be more manageable

Question 23

Advantages of structured programs

Answer 23

Decomposing the program
Each data structure can be tested separately
Different programmers can work on different data structures at the same time hence making it quicker to complete

Question 24

Validating input data

Answer 24

Validation will only check if a data is reasonable not correct, if they are prompted to write date of birth it can check if the year and age makes sense but not if you entered November instead of December

Question 25

Different types of validation

Answer 25

Range check - a number is within a sensible range Type check- data is the right type ie integer Length check - text entered us not too long or short Presence check- checks that some form of data has been entered Format check- checks the format of ie a postcode is appropriate

Question 26

When doing a length check remember that python

Answer 26

Counts including 0 ie a=0, b=1

Question 27

How to check if data is correct

Answer 27

Verification. Ie asking data to be inputted twice and comparing them

Question 28

Maintainability

Answer 28

``` Makes your code understandable Ie use comments Subroutines Meaningful variables Constants appropriately Clarity rather than clever code ```

Question 29

Authentication authentication routines

Answer 29

Biometrics eg optical facial or fingerprint

Question 30

Trace tables are used to help show us

Answer 30

The purpose of algorithms

Question 31

Syntax errors

Answer 31

Mistyping key words or forgetting brackets are syntax errors basically bad grammar this means a program will not compile

Question 32

Logic errors

Answer 32

The program will compile but may not do what you want it to. For example Missing brackets from mathematical equations Loops with incorrect parameters Flawed algorithms Incorrect initialisation of variables

Question 33

Testing a program

Answer 33

Make a plan test with sample data so you already work out what you want it to do and see if it works Trace tables make it clearer to see logic errors as it is more contained

Question 34

High level programming language and def

Answer 34

Translated using a compiler as it is written in basic English Python Java C plus plus

Question 35

Low level language

Answer 35

Processor specific assembly code often in mnuemonics that make it hard for humans to understand. Or Machine code in binary

Question 36

Advantages of high level programming language

Answer 36

Easy to learn. Faster to program in Easier to read so easier to debug and maintain

Question 37

Advantages of low level language - assembly language

Answer 37

Often used in embedded systems such as washin machines or robots Gives programmer complete control over system components so it can be used to manipulate hardware components Very efficient code specific to processor do less memory but executed faster

Question 38

Assemblers.....

Answer 38

Convert assembly language back into machine code

Question 39

Compilers....

Answer 39

Translates high level language into machine codes. Source code(written by programmer ) compiled, object code (machine code)

Question 40

Interpreters also ....

Answer 40

Translate high level programming language into machine code

Question 41

Difference between compilers and translators are

Answer 41

Compilers translates the whole program to produce an executable object code whereas interpreters translates and executes line by line Compiled excuses faster due to this Customers do not need to install compiler bug interpreter must be installed Customers using interpreters can see actual source code and copy it Interpreters are used fro program read compilers are used for software that will be run frequently