Term 2 | Practical | Chapter 3

Question 1

What does a variable refer to in IT?

Answer 1

A variable refers to a memory location that can store data of a particular
data type. Just like variables in Mathematics, variables in programming
can only hold one value at a time.

Question 2

What symbol do we use to indicate that the variable is a string

Answer 2

Single Quotation

‘ ‘

Question 3

Fill in the blanks

______represents a single character, such as a letter, symbol or digit.

Answer 3

Char

Question 4

What is the purpose of integer in coding

Answer 4

Integers can be used in numerical calculations

eg
5
-85

Question 5

What is a real number?

Answer 5

A real number is a positive or negative decimal number. You can perform numerical calculations on real numbers. For Example:

• 68.9
  5. 0

Question 6

What is a Boolean?

Answer 6

A Boolean value can only be one of two values, that is, it can either be True or False. This is often used in programs
where a specific task is only complete if a specific condition is met.

NOTE:
● Boolean values are not included in single quotation marks because they are not strings.

Question 7

Which one is a real number?

-7 OR 5.6

Answer 7

5.6

Question 8

What is a string?
a. a type of variable that hold data values made up of ordered sequences of
characters
b. a data type that holds letters
c. a type of variable that hold characters

Answer 8

C

Question 9

Variable names should use CamelCase. What does this mean?

Answer 9

This means the first word or letter is in
lowercase, and each word afterwards starts with an uppercase letter, for
example, rAmountPaid

Question 10

What are the naming conventions for componets

Answer 10

●component names should describe the task they will
perform or the data
they will hold
● names should use CamelCase.
● component names should start with a three letters prefix that describes the
component type.

Question 11

Before you can use a variable in Delphi, what should you do?

Answer 11

You must first tell delphi to reserve a space for it, In other words, declare a varaible

Question 12

The____statement is used to tell Delphi that variables will be declared

Answer 12

var

Question 13

True OR False

Multiple variables of the same type can be declared on one line, as long as
they are separated by commas

Answer 13

True

Question 14

How do you declare a component?

Answer 14

You don’t. When you place a component onto a form, Delphi automatically inserts the declarations in the Type
section of the code.

Question 15

What do you call this symbol?

:=

Answer 15

Assignment operator

Question 16

On a line 69 a variable was declared, then on line 200 the variable was declared again.

69) iNumber:= 80;
200) iNumber:= 800;

What is the value of iNumber, and Why?

Answer 16

800 because When a new value is assigned the previous value is overwritten/replaced.

Question 17

Why do we need to convert data types?

Answer 17

When data or values are read from an Edit
component, it is always of type string. This
poses a problem when you want to enter
numeric values that will be used in calculations.

Question 18

You can also convert between different data types. This conversion process is
called_______

Answer 18

casting

Question 19

StrToInt

Describe this conversion function
AND
Provide and Example

Answer 19

Converts a string value to an integer
value.

iNum := StrToInt(‘500’);
iAge := StrToInt(edtAge.text);

Question 20

Describe these Conversion Functions

StrToFloat
IntToStr
FloatToStr

Answer 20

Converts a string to a real number
Converts an integer value to a string value
Converts a real value to a string value

Question 21

What are the 3 types of errors?

Answer 21

● syntax errors
● runtime errors
● logic errors.

Question 22

What are Syntax Errors?

Answer 22

Syntax refers to the form and structure of the programming language, which
defines how the symbols and keywords must be combined to format a statement.
In Delphi, the compiler checks your code against this rule. If the compiler does
not understand the statement, then a syntax error is reported.

Question 23

Give 3 common syntax errors?

Answer 23

Common syntax errors include:
● leaving out a semicolon at the end of a statement
● we use a ‘begin …end’ block when grouping statements. Leaving out either
the begin or the end will result in a syntax error
● leaving out the command, var, when declaring variables
● assigning a variable using the equals to sign (=) instead of the assignment
operator (:=)
● misspelling variable names
● using keywords as variable names
● using variables that have not been declared
● not surrounding string values with the single quote marks.

Question 24

For syntax errors, the 1._____ will generally warn you that you have made a mistake
and indicate the line in which the mistake occurs. Delphi will provide you with
information about the error in the 2._____ at the top left or the Messages
panel at the bottom of the Code screen

Answer 24

1. IDE

2. Structure Panel

Question 25

What is a runtime errors?

Answer 25

These errors occur when
the program is running. For example, when division is taking place, the user
enters a zero for the divisor, the computer will immediately give a runtime error
because division by zero is inadmissible.

Question 26

What are logic errors

Answer 26

most dif cult type of error to solve is a logic error. These errors
occur when there are errors in the logic of the program or algorithm. The program
compiles and runs correctly but produces the incorrect results.