Evaluation of expression Using Stack

Duration: 4 min

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Module outline

  1. Quantitative Ability: Percentage, Profit and Loss, Ratio and Proportion (Ratios), Average, Time and Work, Speed Time and Distance, Simple Interest and Compound Interest, Age Problems, Number System, Divisibility Rules, HCF LCM, Algebra, Permutation and Combination, Probability, Data Interpretation, Logarithm, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Speed Mathematics and Basic Mathematics
  2. Logical Reasoning: Seating Arrangements, Puzzle Solving (Puzzles), Data Arrangement, Coding Decoding, Blood Relations, Directions (Direction Test), Ranking, Order and Sequence, Data Sufficiency, Venn Diagram, Inequality, Series (Number and Letter Series) (Numerical Relations and Reasoning), Logical Sequence Of Words, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Analogy, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning)
  3. Verbal Ability: Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Subject Verb Agreement (Verb Noun Agreement), Tenses, Articles, Preposition, Conjunction, Modals, Active Passive Voice (Voice), Direct and Indirect Speech, Vocabulary, Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Sentence Completion (Fill in the blanks), Sentence Correction (Error Correction), Cloze Test (Cloze Passage), Facts, Inference and Judgements
  4. Programming Fundamentals (Technical): C Fundamentals
  5. Data Structures (Technical): Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  6. Algorithms (Technical): Algorithm Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Time Complexity Analysis, Advanced Algorithms
  7. OOPs (Technical): Object Oriented Programming (OOPS)
  8. DBMS (Technical): Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, ORDBMS, Database Security & Authorization, Query Processing & Optimization, Enhanced Data Models, Data Warehousing & Mining, Big Data Systems, NoSQL
  9. SQL (Technical): SQL
  10. Operating Systems (Technical): Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Linux OS, Security, Distributed Systems, Virtual Machines
  11. Computer Networks (Technical): Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security, Mobile Technology, Cloud Computing and IoT, Cyber and Info Security
  12. Software Engineering (Technical): Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  13. Coding/Automata Round: Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Java, Python for Placements by Yash Sir, Pseudo Codes
  14. Personality / Behavioral Assessment: Behavioral Assessment (Behavioral Competency Profiling) (Psychometric Test)
  15. Writing Assessment: English Writing Ability
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture focuses on the application of stacks in computer science, specifically for evaluating arithmetic expressions in postfix notation. The instructor, Sanchit Jain Sir from Knowledge Gate, presents a specific problem from the GATE 2015 exam. The problem asks to evaluate the postfix expression `10 5 + 60 6 / * 8 -`. The solution involves using a stack to store operands and performing operations as operators are encountered. The instructor systematically walks through the expression, pushing numbers onto the stack and performing calculations when an operator appears, ultimately arriving at the correct answer among the provided choices.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video begins with a title slide indicating a 'Break' and the topic 'Application of Stack: Arithmetic Expression Evaluation'. The instructor introduces a GATE 2015 question asking for the result of the postfix expression `10 5 + 60 6 / * 8 -`, with options (A) 284, (B) 213, (C) 142, and (D) 71. He writes the expression on the board and begins the evaluation process. He draws a stack diagram and pushes the first two operands, 10 and 5. Upon encountering the `+` operator, he pops 5 and 10, calculates their sum (15), and pushes the result back onto the stack. Next, he pushes the operands 60 and 6. When the `/` operator is encountered, he pops 6 and 60, performs the division (60 divided by 6 equals 10), and pushes the result 10 onto the stack. At this point, the stack contains 15 and 10, ready for the next operation.

  2. 2:00 – 4:27 02:00-04:27

    Continuing from the previous state, the instructor encounters the `*` operator. He pops the top two elements, 10 and 15, and multiplies them (15 * 10 = 150), pushing the result 150 back onto the stack. He then pushes the next operand, 8, onto the stack. Finally, he encounters the `-` operator. He pops 8 and 150, subtracting 8 from 150 to get the final result of 142. The instructor marks option (C) 142 as the correct answer, completing the step-by-step demonstration of postfix expression evaluation using a stack. He emphasizes the visual representation of the stack growing and shrinking as operations are performed.

This lecture segment effectively demonstrates the practical application of the stack data structure in parsing and evaluating mathematical expressions. By breaking down the GATE 2015 problem, the instructor illustrates the Last-In-First-Out (LIFO) nature of stacks, where operands are stored until an operator triggers a calculation. The example emphasizes the correct order of operands for non-commutative operations like subtraction and division, ensuring students understand how postfix notation simplifies expression evaluation without parentheses. The visual board work reinforces the abstract concept of stack operations.

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