Stack recursion Practice question

Duration: 2 min

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Module outline

  1. Discrete Mathematics: Permutation, Combination and Probability / क्रमचय, संचय एवं प्रायिकता, Set Theory, Relations, Functions, Propositional and Predicate Logic, Graph Theory, Group Theory
  2. Digital Logic: Digital Systems & Boolean Basics, Boolean Expression, Boolean Minimization, Logic Gates & Hardware, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Floating Point Rep
  3. Computer Organization and Architecture: Basics of COA, Programming the Basic Computer, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Pipelining, Multiprocessors
  4. Programming: Language Design, C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++
  5. Data Structures: Introduction to DS, Array, Linked List, Stack, Queue, Tree, Graphs, Hashing
  6. Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  7. Theory of Computation: Grammar, Regular Language Properties, Moore & Mealy Machines, Turing Machines
  8. Compiler Design: Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment, Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Pushdown Automata & CFG, Complexity Theory
  9. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Security
  10. Database Management Systems: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, ORDBMS, NoSQL
  11. Computer Networks: 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
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video presents a C programming problem involving a recursive function named fun. The code snippet includes standard headers and a function definition where fun(int n) checks if n equals 4. If true, it returns n; otherwise, it returns 2 * fun(n+1). The main function calls fun(2) and prints the result. The instructor systematically traces the execution flow on a whiteboard to determine the final output value, demonstrating the mechanics of recursion and stack unwinding.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins the analysis by writing fun(2) on the whiteboard, representing the initial function call from main. He points to the if (n == 4) condition in the code, explaining that since n is 2, the condition is false. This directs execution to the else block, which returns 2 * fun(n+1). He writes return 2 * fun(3) on the board. Next, he traces the call fun(3). Again, n is not 4, so he writes return 2 * fun(4). For the call fun(4), the condition n == 4 is true, so the function returns the value 4. He writes fun(4) = 4 on the side. He then substitutes this value back up the stack: fun(3) becomes 2 * 4 = 8. Finally, fun(2) becomes 2 * 8 = 16. He writes (16) and marks option (C) as correct, crossing out the other choices.

  2. 2:00 – 2:18 02:00-02:18

    The video concludes with the final state of the whiteboard visible. The recursive expansion is complete, showing the hierarchy of calls: fun(2) depends on fun(3), which depends on fun(4). The calculated intermediate values 4, 8, and the final result 16 are clearly written in red ink. The instructor has placed a checkmark next to option (C) 16, confirming the solution. The screen displays the multiple-choice options with the correct answer highlighted, ending the lecture segment.

This lecture effectively teaches the method of tracing recursive code by expanding the call stack and substituting return values. It emphasizes identifying the base case to stop recursion and correctly computing the final result through sequential multiplication.

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