Practice Question (Gate 1998)

Duration: 2 min

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  1. About Course: BTSC About Course
  2. Basics of Computer Science: Basics of COA, Number System, Number Representation
  3. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory
  4. Data Structures & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms
  5. Database Management Systems(DBMS): Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Relational Algebra, SQL, Transaction Management, Concurrency Control, Database Recovery
  6. Networking and Internet: Introduction to CN, Data Communication, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Application Layer, Hardware Basics, Network Access Technologies, Network Security
  7. Cyber Security Basics: Cyber Threats and Malware Attacks, Role of Internet and Web Services, Electronic Data Interchange and E-Commerce, Cyber Safety and Security
  8. C Programming (Programming Fundamentals): C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  9. C++, OOPs & Java (Programming Fundamentals): Java, OOPS with C++
  10. Python (Programming Fundamentals): Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules
  11. Web Development Basics: Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, JavaScript-Basics, HTML Basics
  12. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing
  13. Software and Hardware Tools: MS Office Applications, Unix OS, Linux OS
  14. Emerging Trends. AI & Social Ethics: Artificial Intelligence, Emerging Tech Trends, Society, Law & Ethics
  15. Full Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This short GATE 1998 clip teaches how to convert the infix expression 3 * log(x + 1) - a/2 into postfix notation by building an expression tree and performing a post-order traversal. The instructor first draws the subtree for log(x+1), placing 'log' as a node with '+' below it and 'x' and '1' as leaves. Then the '*' operator is added above, with '3' on the left and the log subtree on the right. Finally, '-' becomes the root, with '*' as its left child and a/2 as its right subtree. The postfix result is obtained by visiting leaves before operators, yielding 3 x 1 + log * a 2 / -. The on-screen text shows the question, the original expression, and handwritten postfix strings, including both a correct traversal and an alternative notation.

Chapters

  1. 0:00 – 1:45 00:00-01:45

    The slide displays the GATE 1998 question 'Compute the postfix equivalent of the following expression' with the formula 3 * log(x + 1) - a/2. The instructor constructs an expression tree: first the 'log' node with '+' child and leaves x and 1, then a '*' node above it with left leaf 3, and finally the '-' root connecting '*' to the a/2 subtree. The postfix traversal is written on screen as 3 x 1 + log * a 2 / -, with an alternative string - * 3 log + x 1 / a 2 also visible.

The central method is infix-to-postfix conversion via expression trees. Operators become internal nodes and operands become leaves; precedence and parentheses determine the tree shape. Postfix notation is read by post-order traversal: left subtree, right subtree, then root. For 3 * log(x + 1) - a/2, the tree has '-' at the root because subtraction is lowest precedence. Its left child is '*', whose children are 3 and log; log's child is '+', with leaves x and 1. The right child of '-' is '/', with leaves a and 2. Traversing gives 3 x 1 + log * a 2 / -. The clip also shows an alternative prefix-like string, but the standard postfix answer is the post-order sequence.

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