Computer Science Test - 10

Correct option is stackone = list()

CONCEPT:

Lists in Python can be created using list() method or by placing the values inside square brackets[], for example

a=[1,2,3] 

or we can create list using list() method and then add elements using append() method

a=list()

a.append(1)

a.append(2)

a.append(3)

In the above question

Option 2 stackone != list() 

// here not-equal-to operator is used which is a comparision operator. 

Option 3 stackone = list[]

// invalid syntax list[]

Option 4 stackone = stacklist() 

//  error as there is no method named stacklist() 

The correct option is overflow

CONCEPT:

The basic operations of the stack may hit a special condition or raise an error like:

Underflow happens when we try to pop (remove) an item from the stack when the stack is already empty. 

Overflow happens when we try to push an item onto a stack, when the stack is full or out of memory.

Additional Information

Stack is a linear data structure that follows a last in first out order.

In python, we can implement a stack using a list data structure by using append() and pop() methods

Basic Operations of Stack:

• Push: Adding an item to the top of the stack is done using the push operation.
• Pop: Removing an item from the top of the stack is done using the pop operation.

In python, we can perform

Push item using the append() method

Pop top item using the pop() method 

The correct Option is operators

CONCEPT:

While performing the conversion of an expression, we need to follow some set of rules (operator precedence and associativity rules) to evaluate the result. 

The position of operators is an important factor to decide the type of expression and to differentiate between the precedence and associativity of two different operators stack data structure is used.

That is why only operators are pushed onto the stack.

Example: Converting infix expression to postfix using stack

Infix: (a+b)-c

Postfix: ab+c-

With the above example, we can say that only operators are PUSHED onto the stack.

Correct option is Returns the size of stack.

CONCEPT:

In python def keyword is used to define a function , it is placed before a function name.

Syntax:

def function_name: 

     definition statements...

In the above question pops is a user-defined function that takes a stack named "stackname" as argument

and returns the length of stack using len() function.

Example: Let stackname=[1,2,3] is a stack which contains 3 elements

On calling the pops(stackname)  function, it will return 3 as length of stack.

The correct option is rightmost

CONCEPT:

In python, the append() method adds an element to the end of the list.

The pop() method removes the item at a given index from the list and returns the removed item.

If no index value is passed, the default index -1 is passed as an argument (index of the last item) and the last element is removed from the list.

The correct option is underflow

CONCEPT:

Stack is a linear data structure that follows a last in first out order.

It contains a top pointer that points to the topmost element of the stack.

The insertion and deletion of items take place from one end only using the top pointer.

Basic Operations of Stack:

• Push: Adding an item to the top of the stack is done using the push operation.
• Pop: Removing an item from the top of the stack is done using the pop operation.
• IsEmpty: Check if the stack is empty.
• IsFull: Check if the stack is full.
• Peek: It returns the item which is on top of the stack without removing it.

These basic operations may hit a special condition or raise an error like:

Underflow happens when we try to pop (remove) an item from the stack when the stack is already empty. 

Overflow happens when we try to push an item onto a stack, when the stack is full or out of memory.

The correct Option is Stack

CONCEPT:

While performing the conversion of an expression, we need to follow some set of rules (operator precedence and associativity rules) to evaluate the result. 

The position of operators is an important factor to decide the type of expression and to differentiate between the precedence and associativity of two different operators stack data structure is used.

Stack data structure has various applications:

• Expression Conversion
• Expression Evaluation
• String Reversal
• Parenthesis Checking
• Syntax Parsing

Example of infix to postfix conversion using stack.

Infix: (2+5)-3

Postfix: 25+3-

Correct option is Stack

CONCEPT:

A Stack is a widely used linear data structure in which insertions and deletions of an element can occur only at one end.

Stack data structure has various applications:

• Expression Conversion
• Expression Evaluation
• String Reversal
• Parenthesis Matching
• Syntax Parsing

Correct option is Infix

CONCEPT:

An expression mainly consists of operands, operators, and symbols.

These must be arranged according to a set of rules so that expressions can be evaluated using the set of rules.

There are mainly three notations used for writing expression:

Infix notation: When the operator is written in between the operands it is known as infix notation. Example 2+5

Prefix notation: When the operator is written before the operands it is known as Prefix notation. Example +25

Postfix notation: When the operator is written after the operands it is known as Postfix notation. Example 25+

The correct option is Midfix

CONCEPT:

There are mainly three notations used for writing expression:

Infix notation: When the operator is written in between the operands it is known as infix notation. Example 2+5

Prefix notation: When the operator is written before the operands it is known as Prefix notation. Example +25

Postfix notation: When the operator is written after the operands it is known as Postfix notation. Example 25+

But there is no notation like Midfix to represent an expression.