Numerical data.

Group 3
Adewumi ezekiel
Computer science

F a j u k o M i c h a e l
A d e w u m i E z e k i e l
E t u k u d o A n d y
A f i a K e n n e d y

ORDER OF PRESENTATION
ETUKUDO ANDY-will introduce the project and talk
on the order in which the project will be presented and
also give a brief knowledge about his contribution in
the group for five (5) minutes.
ADEWUMI EZEKIEL- will present the project titled
“NUMERICAL DATA” and also give a brief knowledge
about his contribution in the group for seven (7)
minutes.
FAJUKO MICHEAL-will run the program that
concerns the project and also give a brief knowledge
about his contribution to the group for seven (7)
minutes.
Finally, AFIA KENNEDY-will talk on the conclusion
and how the project relates to our previous lectures
and also give a brief knowledge about his contribution
to the group for five (5) minutes.

Arithmetic expression is a valid arrangement of variables,
constants , operators ,operands and parentheses.
e.g
This an expression=x²-(4bc)
where x=variables
B and c=constants
-sign =operators
()sign=parenthesis
4=operands
There are five (5) operations in arithmetic expression that can
be written in java the arithmetic operators are:
Addition(+)
Subtraction(-)
Multiplication(*)
Division(/)
Modulo division (%)

The Evaluation of the Arithmetic Expression
in java is shown below;
•10+25=35
•50-15=35
•6*3=18
•25/5=5
•9%2=1

Precedence Rule
When two or more operators are present in an
expression, we determine the order of
evaluation by following the precedence rules.
Order of Precedence
Bracket( )
Unary operators such as minors sign (-) and plus sign
(+)
Multiplication operator such as multiplication (*),
Division (/) and modulo division (%)
Additive operator such as minors(-) and addition(+)
I call it BUMA

Example 1
6 + ((37 % 8) / 5) =
6 + ( 5 / 5) = 7
Evaluate
(7 * (10 - 5) % 3) * 4 + 9
(7 * 5 % 3) * 4 + 9
(35 % 3) * 4 + 9
2 * 4 + 9
8 + 9
17

1. Write the source code in a .java file
2. Compile the source code into byte code creating a .class file
3. JVM interprets the byte code into machine language as 1s and 0s
and the computer then executes the instructions

The Math class is a type of standard class in
the java.lang package. The Math class contains
methods that perform various mathematical
functions.
Example: Square Root
a = Math.sqrt(9.0)
a would receive the value of 3.
Example: Exponents
a = Math.pow(4.0, 2.0)
a would receive the value of 16.
where Math is the class, pow is the method
and the rest are the parameters.

Mathematical Syntax Operation Java Description
Math.sqrt(x) square root of x
Math.pow(x, y) x raised to the exponent y
Math.abs(x) absolute value of x
Some Math Class Methods

16
( ( ( Math.pow( ( ( 1 + Math.sqrt( 5 ) ) / 2 ),fibonacciNum ) ) - ( Math.pow( ( ( 1-
Math.sqrt( 5 ) ) / 2 ), fibonacciNum ) ) ) / Math.sqrt( 5 ) );
Write a formula with the use of mathclass
method that accepts N and displays FN.

The DecimalFormat class (which is part of the
java.text package) is one way to format
numbers.
To format a number using the DecimalFormat class,
a number of steps are required. In the following
example, we will format a number to two decimal
places.

1. Import the java.text.DecimalFormat class.
import java.text.DecimalFormat;
2. Now you must create a DecimalFormat object to format the text
according to a pattern that you specify.
// Declare and initialize DecimalFormat object
DecimalFormat df = new DecimalFormat(“.00”);
df is the name given to the DecimalFormat object we have created
# is a placeholder object that will be removed if there is not a
digit at that location
0 is a placeholder that will show up as zero if a digit is not found at
that location
3. Now we can use the DecimalFormat object to format your
number.
System.out.println(df.format(234.5678));
The above expression outputs 234.57.
The format pattern #.00 asks that a number be converted into
four characters – i.e. one digit to the left of the decimal separator,
a decimal separator, and two digits on the right.

21
DecimalFormat decFor = new DecimalFormat(String pattern);
If I wanted to format the number to zero decimal places,
my DecimalFormat object would be created as
follows:
DecimalFormat df = new DecimalFormat(“#”);
The above program would output the number 234.5678
would be outputted as 235.
class
parameterVariable name

EXAMPLE
import java.text.DecimalFormat;
class Deci {
public static void main(String args[]) {
//formatting numbers up to 2 decimal places in Java
DecimalFormat df = new
DecimalFormat("######.00");
//formatting numbers up to 3 decimal places in Java
df = new DecimalFormat("######.000");
}
}

It will display something like this;

•The input returned from the input dialog box is a
string. If you enter a numeric value such as 123, it
returns “123”. To obtain the input as a number,
you have to convert a string into a number.
•To convert a string into an int value, you can use
the static parseInt method in the Integer class as
follows:
int intValue = Integer.parseInt(intString);
•where intString is a numeric string such as “123”.

To convert a string into a double value, you can use
the static parseDouble method in the Double class
as follows:
double doubleValue
=Double.parseDouble(doubleString);
where doubleString is a numeric string such as
“123.45”.

It is an open code and ready to supply input
data. Typically it corresponds to keyboard input
or another input source specified by the user.
System.in means by inputting the attributes and
method or data.
NOTE -The data collected by the system.in
object is character data, even if they are
entered as numeric digits. Therefore if the
application performs any calculation, the input
character, it must first be converted to
primitive data type before it is used.

It is an open and ready to accept output
data. Typically it corresponds to display
output or another output destination
specified by the user. Writing character
to the system.out using method print()
or print() displays these character on
your screen.

32
GregorianCalendar class is a type of standard class
used for manipulating calendar information such as
year, month, day, hour, minute and second from a
Date object..
 Firstly, identifying the package in which a class
belongs is very important
Therefore
 (Java.util.Gregorian-Calendar is a concrete
subclass of Calendar);

33
However they are constant defined in the calendar class for
retrieving different fragment of calendar/time which are;
Parameters and Constant defined
year - the value used to set the YEAR time field
in the calendar.
month - the value used to set the MONTH time
field in the calendar. Month value is 0-based. e.g.,
0 for January.
WEEK-the constant value for the days of week.
date - the value used to set the DATE time field
in the calendar.
hour - the value used to set the HOUR_OF_DAY
time field in the calendar.

 How to Constructs a GregorianCalendar
with given date and time set for the
default time
GregorianCalendar today = new
GregorianCalendar( );
public GregorianCalendar
(int year,
int month,
int date,
int hour,
int minute,
int second)

And it is possible to create a new GregorianCalendar
object that represents today as
Or specifically presenting the day as January7,
2014, by passing year, month, and day as the
parameters
e.g.
 GregorianCalendar independenceDay = new
GregorianCalendar (2014, 3, 7);
 The value of 3 in the second parameter means
April because the value of the January is 0; and
the value of February which is the second month
of the year is 1 so therefore; the, value of April
is 3

38
Java Data Types
object
array interface class
primitive
integral boolean
byte char short int long
floating point
float double

 When a new Data values is created, Java
allocates space from a pool of memory
called the stack to the variables

Java Primitive Data Types
 Primitive data value is also known as
(numerical data value) used to compute the
sum and the difference of variables (x and
y) in a Java program
 we must first declare what kind of data will
be assigned to them after assigning values
to them, then computing their sum and
difference is made possible, to declare
that the type of data assigned to them is
an integer, we write
 int x, y;

After declaration is made, memory is
allocated to store data values for x and y.
 These memory locations are called
variables, and x and y are the names we
associate with the memory locations.
When declaration is made, we can
assign only integers to x and y but not
real numbers.
 However there are six numerical data
types in Java: byte, short, int, long,
float, and double.

 The difference among these six
numerical data types are their range of
values they can represent
 Also a data type with a larger range of
values is said to have a higher precision
data type.
 Double has a higher precision than the
data type float.

 Memory size for data types
Every data type has some memory size defined. This
enables that whenever a variable is declared, the memory
size is automatically defined
 Default value:
Every primitive data type has default values defined. When
the programmer does not declare to assign any values to the
variables, these default values will be assigned by the
Virtual machine during the object instantiation.
 Range of values the data types can represent
It is extremely important to understand what are the min
and max range of values a data type can be able to hold.

This is syntax for declaring primitive data value
<data type> <variables>;
num1 38
num2 96
Before:
num2 = num1;
num1 38
num2 38
After:
Int number1,number2;
number1 = 138;
number2 = number1
When number2 is declared
as a variable it overwrite the
reference in number1

Object Data type
These are also variables (they can be change) but the
only difference is the content because a variable in an
object contains an address where the object is stored.
Without executing a new command, no new object is
created, two variables can refer to the same object as
the object having two distinct names
 Before a memory is allocated to an object in a program,
it must be declared and initialized
An object declaration simply declares the name
(identifier) that is used to refer to an object.
Where <object names> is a sequence of object names
separated by commas and <Class name> is the name of a
class to which these objects belongs. The name of an
object and the class to which the object belongs

This is the syntax for object declaration:
<Class name> <object names>;
 When an address of an object is
executed and memory space is
allocated
 When the class of an object is
executed there’s a space memory
allocated to it

For object
name2 = name1;
name1
name2
Before:
"Steve Jobs"
"Steve Wozniak"
name1
name2
After:
"Steve Jobs"

From the open book test, we have been drilled to read
and understand the concept of java in chapter two of
McGraw introduction to java. From the first topic, we
learnt about the six programming phases which are;
understand the program, Plan the logic, Code the
program, Test the program etc and this was used while
practicing and working out the java program for each
of the bullet point in question. Class is also the
template in object-oriented programming and it can
also be related to pseudocode.

Numerical data.

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