Chapter 3 Data Types and Structures

Question 1

What is a data type?

Answer 1

A data type is the type of data that is used in the program. The way in which the data is manipulated will depend on the data type.

Question 2

What is declared at the start of the program alongside a variable?

Answer 2

An identifier and a data type.

Question 3

What are the 3 main data types?

Answer 3

Numeric, alpha-numeric and boolean.

Question 4

What two types of numeric data types are there?

Answer 4

Integer and Real.

Question 5

What two types of alpha-numeric data types are there?

Answer 5

String and Character

Question 6

What kind of answer does a boolean have?

Answer 6

TRUE/FALSE or YES/NO

Question 7

What kind of numbers can an integer be?

Answer 7

Whole

Question 8

Can a real value have a decimal value?

Answer 8

Yes

Question 9

What does a boolean do?

Answer 9

It can only have two values and is often used to see if a condition has occurred or a value has been met.

Question 10

How many digits does a character normally have?

Answer 10

One

Question 11

Which data type is used for longer pieces of text?

Answer 11

A String

Question 12

What are the two data structures?

Answer 12

Arrays and Records.

Question 13

What is an Array?

Answer 13

An array is a piece of data that contains several pieces of similar data.

Question 14

What is meant by an element of an array?

Answer 14

Elements of an array are pieces of data with the same data type, similar memory size and are usually stored next to each other.

Question 15

What orders the elements?

Answer 15

The index.

Question 16

What are the bounds of the index?

Answer 16

The highest and lowest values.

Question 17

Why does using an array help when declaring the data?

Answer 17

You can declare all the statements using the array by using one statement.

Question 18

What is a record?

Answer 18

A record is used to store several data types under one identifier.

Question 19

What is the name given to individual values in a record?

Answer 19

A field.

Question 20

In which file types will removing a piece of data leave a gap?

Answer 20

Serial, Sequential and Indexed Sequential.

Question 21

What is the difference between a sequential file and an indexed sequential file?

Answer 21

An indexed sequential file has a index.

Question 22

What is the formula for finding a record in a direct access file?

Answer 22

Address of record number (n)=Beginning of file + (n-1) * size of record.

Question 23

What are the 4 steps in estimating a file size?

Answer 23

1. Work out the size of each field in the record in bytes.
2. Add field sizes together to get the size of one record.
3. Multiply the size of one record by the number of records in the file.
4. Add 10% to accommodate for the extra storage needed to manage the file.

Question 24

How do you change from bytes to kilobytes?

Answer 24

Divide by 1000.

Question 25

Why don’t you divide by 1024?

Answer 25

Because it is only an estimate.