abstract data types sir joseph lindo university of the cordilleras

Joseph Lindo

AbstractDataTypesSir Joseph Lindo

University of the Cordilleras

Joseph Lindo

ADT

Abstract Data Types

StackAll insertions and deletions are made at one end

top of the stackLast In First Out (LIFO)Some analogiesStack of trays Books in a table

List

Stack

Queue

Case

Array

Stack

Joseph Lindo

ADT

Abstract Data Types

Stack ApplicationArithmetic Expression

INFIXPREFIXPOSTFIX

List

Stack

Queue

Case

Array

Stack

Joseph Lindo

AbstractDataTypes

-- end --Sir Joseph Lindo

University of the Cordilleras

Joseph Lindo

AbstractDataTypes-- end na --Sir Joseph Lindo

University of the Cordilleras

Joseph Lindo

Stack in real life

Online Activity

• Think of real life activities, scenarios or things that applies the concept stack.

• Post answer as comment on our facebook group, in your specified block (F,D and G)

• You are not allowed to have the same answer

Joseph Lindo

Major Operations

Stack

• PUSH (Object)- add object into the top of the stack

• POP- remove object into the top of the stack

• Others- isEmpty- isFull- PEEK

Joseph Lindo

INFIX Notation

Stack

To add A, B, we writeA+B

To multiply A, B, we writeA*B

The operators ('+' and '*') go in between the operands ('A' and 'B')

Joseph Lindo

PREFIX Notation

Stack

Instead of saying "A plus B", we could say "add A,B " and write

+ A B

"Multiply A,B" would be written* A B

Joseph Lindo

POSTFIX Notation

Stack

Another alternative is to put the operators after the operands as in

A B +and

A B *

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Notations

Stack

The terms infix, prefix, and postfix tell us whether the operators go between, before, or after the operands.

Pre A In B Post

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Notations

Stack

Parenthesis

Evaluate 2+3*5.+ First:

(2+3)*5 = 5*5 = 25* First:

2+(3*5) = 2+15 = 17

INFIX notation requires Parentheses.

Joseph Lindo

Notations

Stack

What about PREFIX? + 2 * 3 5 =

= + 2 * 3 5 = + 2 15 = 17

* + 2 3 5 = = * + 2 3 5 = * 5 5 = 25

No parentheses needed!

Joseph Lindo

Notations

Stack

What about POSTFIX?

2 3 5 * + = = 2 3 5 * + = 2 15 + = 17

2 3 + 5 * = = 2 3 + 5 * = 5 5 * = 25

No parentheses needed here either!

Joseph Lindo

Notations

Stack

Conc lusion

Infix is the only notation that requires parentheses in order to change the order in which the operations are done.

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FPE

Stack

A FPE has exactly one set of Parentheses enclosing each operator and its operands.

Which is fully parenthesized?( A + B ) * C

( ( A + B) * C ) ( ( A + B) * ( C ) )

Joseph Lindo

INFIX to PREFIX

Stack

Move each operator to the left of its operands & remove the parentheses:

( ( A + B) * ( C + D ) )( + A B * ( C + D ) )

* + A B ( C + D )* + A B + C D

Order of operands does not change!

Joseph Lindo

INFIX to PREFIX

Stack

Practice:

1.( ( A + ( B – D ) ) * C)

2.( ( ( C * B ) / ( E + B) )/ F )

Joseph Lindo

INFIX to POSTFIX

Stack

Move each operator to the left of its operands & remove the parentheses:

( ( A + B) * ( C + D ) )( A B + * ( C + D ) )

A B + (C + D ) *A B + C D + *

Order of operands does not change!

Joseph Lindo

INFIX to PREFIX

Stack

Practice:

1.( ( A + ( B – D ) ) * C)

2.( ( ( C * B ) / ( E + B) )/ F )

Joseph Lindo

AbstractDataTypes

-- end --Sir Joseph Lindo

University of the Cordilleras

Joseph Lindo

AbstractDataTypes-- end na --Sir Joseph Lindo

University of the Cordilleras

Joseph Lindo

Comprehension Check