Tipe Data

Algorithm Writing Rules

Algorithm Text three blocks: 2. Header 

- algorithm name - brief description about the program

2. Declaration - definition of all variables, constant values, etc

3. Description - the main part

(1) Header Algorithm Circle_Area

{ calculating the area of a circle. Input will be the radius of the circle }

(2) Declaration Declaration { constants } const phi = 3.14 { type } type Point : record {cartesian coord.} < x: integer, y: integer >

(3) Description Description read (c,d) if c < d then e  a+b else e  a-b endif write e

Working example Algorithm Calculating_Mean { calculating the mean of an integer group } Declaration X : integer N : integer K : integer SUM : integer AVE : real

{ input } { the number of the input } { pointer } { the sum } {the mean }

Description read (N) k1 SUM  0

{ read the number of the data} {initial value for looping} {initial value of the SUM}

while k <= N do {looping until k = N } read (x) SUM  SUM + x {accumulation} kk+1 endwhile AVE  SUM / N Write (AVE)

{averaging} {final output}

Pseudo code  descriptive  using

similar language  programming  no single standard •example: variable X is given the value of 0. X 0 variable X is given the value of previous X plus 2 X  X+2

Pseudo code (2)  Reading

input data x Read (x)  Printing output data x Write (x)

Pseudo code – condition  Determine

positive or negative

if X => 0 then Write ("positive") else Write ("negative") Endif

Pseudo code – loop  total

accumulation of the first 100 numbers, starting value x = 1 x 1 While (x <=100) Do Accum  Accum + x x  x+1 Endwhile

Pseudocode For (x  1 to 100) Do Accum  Accum + X Endfor X 1 Repeat Accum  Accum +1 X X+1 Until X > 100

Flowchart  Graphical

representation  Easy to understand  Avoid mis-interpretation  Think systematically

Flowchart – the symbols 1

3

Start / Stop 2. Initial value 3. Read / print 4. Process 1.

2

4

Flowchart – the symbols (2) 5

6

7

5. Condition checking 6. Connection @ one page 7. Dokumen 8 Predefined process

8

Flowchart - example  Calculate

shape Input: L, W

the area of a rectangular START Read L, W Calculate A=LxW Print A

FINISH

Types, names and values Boolean Logics  Type : boolean  Value : 0 (false) or 1(true)  operations  logical operations not, and, or, nor, xor 

a

not a

True

False

False

True

(1) Boolean logics A True True False

B True False True

False

False

A and B A or B True True False True False True False

X true, y false, Z true (x and y) or z ?? x and (y or z) ?? not (x and z) ??

False

A xor B False True True False

(2) Integer  Type

name: integer  Value:  Theoretical

: (+) infinite to (-) infinite  But we can make a limitation  saving memory allocation Example: @TP7 type

Value

Byte

0 … 255

Shortint

-128 … 127

Word

0 … 65535

Integer

-32768 … 32767 ( 16-bit = 2 byte)

longint

-2^32 … 2^32-1 (32-bit)

(16-bit)

Integer - operations  Arithmetics 

(+); (-); (*); div; mod



10 mod 3 (result: 1) 10 div 3 (result: 3) 10 & 3 is operands, mod is operator

 

•

Comparisons < ; > ; = ; >= ; <= ; <> (24 div 3) <> 8 (false)

(3) Real  18.0

; 0.065 ; 16.3E-2

• Type name: real • Value: – we make a limitation  saving memory allocation Example: @TP7 type

Value

Real

2.9 E-39 to 1.7 E38

Single

1.5 E-45 to 3.4 E38

Double

5 E-324 to 1.7 E308

Extended

3.4 E-4932 to 1.1 E4932

6 byte

Real - operations  Arithmetics 

(+); (-); (*); /;



10 / 4 (result: 2.5 ) 10 & 3 is operands, / is operator



•

Comparisons < ; > ; >= ; <= ; <>

(3) Character  Alphanumerics  1,2,#,%,&,A,a

 Type

name: char  Constant  using ‘ ' 8  integer '8'  character

Character - operations  Comparison

=, <>, <=, >= 't' = 't' true 't' = 'T' false

(4) Record  Consist

of one or more fields  Each field may store data with any basic type (boolean, integer, etc) field 1

field 2

…

field n

type Point : record < x : real, y : real > type Point : record < x , y : real >

Example ID

Name

Course Code

Mark

Type StudMark : record < ID

: integer

Name: string

{student ID} {student name}

CourseCode : string { Course Code} Mark: char >

{A/B/C/D/E/F}

NAME  As

an identifier to ‘something’  Must be unique  ‘Something’: 1. Variable Declaration X, mark : real K: integer C: char

Name (2) 2. Constant Declaration const phi = 3.14 const Nmax = 100 const pass = ‘xyz’

Name (3) 3. Customized Type Declaration Type Point : record <x, y : real> P : Point { P is a variable referring to a type name of Point}

Naming Convensions 1. 2. 3. 4.

Begin with an alphabet, not numbers, space or special characters Using only alphabets, number or underscore ‘_’ No space; Must be declared.

Incorrect Naming !! 6Point

{ begin with number}

Student name

{ space between single name}

Hey!

{ special character}

VALUE  The

value of the already-known data types (variables, constants).

Assigning value (1) 1.

Direct Assignment k5 {assign a value of ‘5’ to k} var1  var2 {assign a value from var2 to var1}



The value recorded will be the last one.

Example Declaration Type point record <x, y: real> K: integer Distance: real Found: boolean P : point

K 5 Distance  0.03 Found  false P.x  5 P.y  10

K 5 distance 0.03 Found false P.x 5 P.y 10

Using expression ca+b Determinant  b^2-(4*a*c)  Same

name types must be used

a  a+2

?

Example Declaration M,P : integer M 16 P  M*2 M  P + 100 P P + M

M ?? P ??

Assigning value (2) 2. Using input devices Declaration

Declaration

Type point record <x, y: real>

Type point record <x, y: real>

K: integer Distance: real Found: boolean P : point

K: integer Distance: real Found: boolean P : point

K 5 Distance  0.03 Found  false P.x  5 P.y  10

Read (K) Read (Distance) Read (Found) Read (P.x, P.y)