2021 Paper 2

Question 1

differences between a 1D array and a 2D array?

Answer 1

• 1D is a row , 2D is a table
• Each element in 1D is a single value, each element in 2D is a 1D array

Question 2

how is the ceaser cipher a weak encryption algorithm

Answer 2

• The number of keys are limited, making it easy for brute force to decrypt
• It can be easy to find commonly used letters and guess the key

Question 3

state what is meant by a built in subprogram

Answer 3

a subprogram that has already been defined

Question 4

does the key go on the left or up? (viginere)

Answer 4

left

Question 5

binary > linear search

Answer 5

• can be quicker than a linear search, as it does not have to examine each item in the list
• halves the list each time so it can be faster to find an item