Infix to Postfix Conversion Using Stack in DSA C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of converting an infix expression to postfix?

To make it easier for computers to evaluate expressions without worrying about operator precedence or parentheses.

beginner

In the context of infix to postfix conversion, what data structure is primarily used and why?

A stack is used to temporarily hold operators and manage their precedence and associativity during conversion.

beginner

What does the precedence of operators mean in infix to postfix conversion?

Precedence defines the order in which operators are applied; higher precedence operators are applied before lower precedence ones.

intermediate

Explain what happens when a closing parenthesis ')' is encountered during infix to postfix conversion.

Operators are popped from the stack and added to the postfix expression until an opening parenthesis '(' is found, which is then discarded.

beginner

Why are operands added directly to the postfix expression during conversion?

Because operands do not affect operator precedence and should appear in the output in the same order as in the infix expression.

Which data structure is used to hold operators during infix to postfix conversion?

A Stack

B Queue

C Array

D Linked List

A stack is used because it allows easy access to the last operator inserted, which is needed to manage precedence.

What should be done when an operand is encountered in the infix expression?

A Push it onto the stack

B Add it directly to the postfix expression

C Ignore it

D Pop operators from the stack

Operands are added directly to the postfix expression as they appear.

When an operator with lower precedence is encountered, what happens to operators on the stack with higher or equal precedence?

A They are popped and added to postfix

B They remain on the stack

C They are discarded

D They are pushed again

Operators with higher or equal precedence are popped to maintain correct order in postfix.

What is the role of parentheses in infix to postfix conversion?

A They are added to postfix expression

B They are converted to operators

C They change operator precedence temporarily

D They are ignored

Parentheses temporarily change precedence by grouping expressions.

At the end of the infix expression, what should be done with remaining operators in the stack?

A Discard them

B Ignore them

C Push more operators

D Pop and add them to postfix expression

All remaining operators must be popped and added to the postfix expression to complete conversion.

Describe step-by-step how to convert the infix expression 'A + B * C' to postfix using a stack.

Think about operator precedence and when to pop from the stack.

Explain why a stack is the best data structure for infix to postfix conversion.

Consider how operators are processed in reverse order of arrival.