Stack

Info

Stack docs

Author

Gourav <gouravpatel11072@gmail.com>

Date

2020-11-30 (Mon, 30 Nov 2020)

Description

Added stack operations and infix to postfix.

Quick Start Guide

stack :- Stack is a linear data structure which follows a particular order in which the operations are performed. The order may be LIFO(Last In First Out) or FILO(First In Last Out).

A stack allows access to only one data item: the last item inserted. If you remove this item, you can access the next-to-last item inserted, and so on.

A stack is also a handy aid for algorithms applied to certain complex data structures. In “Binary Trees”, we’ll see it used to help traverse the nodes of a tree.

Notice how the order of the data is reversed. Because the last item pushed is the first one popped.

commonly implemented with linked lists but can be made from arrays too.

operations of stack: pop(), push(), tos(), isEmpty(), display().

# import the required data structure
>>> from pythorn.data_structures.stack import Stack

# creating a stack
>>> a = Stack()

# push elements
>>> a.push(5)
>>> a.push(20)
>>> a.push(13)

# displaying full stack
>>> a.display()
[5, 20, 13]

# top element
>>> a.tos()
13

# poping the element
>>> a.pop()
13
>>> a.isEmpty()
False

Example Code for Infix To Postfix

Infix expression:The expression of the form a op b. When an operator is in-between every pair of operands.

Postfix expression:The expression of the form a b op. When an operator is followed for every pair of operands.

# importing Stack and Infix_Postfix
>>> from pythorn.data_structures.stack import Stack
from pythorn.data_structures.stack import Infix_Postfix

# creating a stack
my_stack = Stack()

# My Expression
my_exp = "a+c-*/dsefj-+//jk"

# passing stack and expression to the Infix_Postfix class
infixpostfix = Infix_Postfix(my_exp,my_stack)
infixpostfix.infixToPostfix()
'a c + * d s e f j / - - / j k / +'

Stack Programs

Author : Robin Singh

Programs List:

1.Stack

2.Infix To Postfix Conversion Using Stack

3.Integer To Binary Conversion Using Stack

Stack

class pythorn.data_structures.stack.Stack

Stack implementation

push(item)

Pushes an item into the array

pop()

Pops the top element from the stack, and return -1 if the stack is empty

tos()

returns the top element of the stack, else return -1 if stack is empty

size()

returns the length of the stack, else returns -1 if stack is empty

isEmpty()

checks if the stack is empty or not and returns boolean value

display()

if there is an element in the stack then it prints the full stack ,else returns -1

static get_code()

Returns

source code

static time_complexity()

Returns

time complexity

Infix To Postfix

class pythorn.data_structures.stack.Infix_Postfix(expression=None, stack=None)

Infix To Postfix conversion

static oper(char)

Function of checking whether the given character is an operator or not.

infixToPostfix()

main function for converting infix to postfix using stack.

Returns

converted expression

static get_code()

Returns

source code

Integer To Binary

Example Code for Integer To Binary

# importing Stack and Integer_Binary
>>> from pythorn.data_structures.stack import Stack
>>> from pythorn.data_structures.stack import Integer_Binary

# creating a stack
>>> my_stack = Stack()

# My Number
>>> my_num = 45

# passing my_stack and my_num to the Integer_Binary class
>>> integerbinary = Integer_Binary(my_num,my_stack)
>>> integerbinary.IntegerBinary()
'101101'

class pythorn.data_structures.stack.Integer_Binary(Number=None, stack=None)

Integer To Binary Conversion

static get_code()

Returns

source code