Week 11 Part 1

Question 1

• What is an array?

Answer 1

o A collection of values having the same data-type stored in the computers memory in a linear, contiguous manner

Question 2

o Real life examples that can be represented as Arrays

Answer 2

 Alphabet = index system
 Prices of each item for sale in a store
 Amount of gasoline to refuel a car each month

Question 3

o What would a declared array called prices (num) look like with an element size of 3

Answer 3

num[] prices = new num[3]

Question 4

o What are the 3 parts of an array declaration?

Answer 4

 Data type, variable name, size

Question 5

o By convention arrays have ______ names

Answer 5

 plural

Question 6

o Each storage location in an array is referred to as an

Answer 6

 Element

Question 7

o Each element in an array is accessed using a

Answer 7

 Subscript, also called an index

Question 8

“Populating an array” means

Answer 8

 Initializing the elements with data

Question 9

o The lowest index for an array is _, the max index is the array size minus _

Answer 9

 0, minus 1

Question 10

o Meaning: Array lower bound and upper bound

Answer 10

 Lowest index value [0], highest index value [size-1]

Question 11

o Using an index value that is outside of the array bounds will cause problems, such as (2 cases)

Answer 11

 Best case - Run time error and crash
 Worst case - Corrupts memory that is not part of your program, causing other programs/OS to crash

Question 12

o Java arrays enforce _____ ______, with a run-time exception causing a crash

Answer 12

 Array bounds

Question 13

o Why is it important to enforce array bounds in programming?

Answer 13

 Can be used as a security exploit by hackers, to corrupt memory and run viruses

Question 14

o Memory in computers is organized a sequence of _ ____ blocks of _ ___ each

Answer 14

 1 byte, 8 bits

Question 15

o Each byte in the computer has a unique ______ _______

Answer 15

 Memory address

Question 16

o Arrays and Memory: size of array’s elements is determined by the arrays

Answer 16

 Data type.

Question 17

o Arrays and Memory: Integers in Java occupy 4 bytes of memory. If it’s an integer array, each element will occupy

Answer 17

 4 bytes of memory, or 32 bits

Question 18

o Arrays and Memory: Each element of an array is placed ___________ after the other, in a ___________ manner

Answer 18

 Immediately, contiguous

Question 19

o How many bytes of memory would this occupy? Int number [4]

Answer 19

 16 bytes, 128 bits (4x4bytes), (4x32bits)

Question 20

o In order to find an array in memory, the system uses

Answer 20

 The subscript, datatype, and name to perform a calculation and jump to the correct memory location

Question 21

o Explain these
1. int value = numbers[0]
2. numbers[0] = 33

Answer 21

 1. Read from a single array element, 2. Write to a single array element

Question 22

o Num numbers[5] = 3.3, 4.4, 5.5 which index will these elements attach to?

Answer 22

 Leftmost will attach to 0, and so on*

Question 23

o T/F – Each element in an array diagram is represented by a single box, regardless of the number of bytes

Answer 23

True

Question 24

o An Array is a ____ of data items in ___________ memory locations

Answer 24

group, contiguous