Stack recursion Practice question
Duration: 2 min
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Module outline
- English Comprehension/Verbal Ability: Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Vocabulary, Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Subject Verb Agreement (Verb Noun Agreement), Tenses, Verb, Articles, Preposition, Conjunction, Pronoun, Noun, Adjectives, Adverb, Modals, Cloze Test (Cloze Passage), Active Passive Voice (Voice), Direct and Indirect Speech, Sentence Construction
- Logical Ability: Coding Decoding, Directions (Direction Test), Analogy, Inequality, Data Sufficiency, Series (Number and Letter Series) (Numerical Relations and Reasoning), Syllogisms, Seating Arrangements, Puzzle Solving (Puzzles), Blood Relations, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Ranking, Order and Sequence, Logical Sequence Of Words, Data Arrangement, Venn Diagram, Calendar, Clock
- Quantitative Ability: Logarithm, Permutation and Combination, Probability, Profit and Loss, Speed Time and Distance, Mixture and Alligation, Partnership, Simple Interest and Compound Interest, Percentage, Ratio and Proportion (Ratios), Average, Time and Work, Pipe and Cistern, Number System, Divisibility Rules, HCF LCM, Algebra, Powers and Exponents (Surds and Indices), Mensuration and Geometry, Age Problems, Data Interpretation, Sequence and Series (Series)
- Basic Analytical Ability: Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analytical Reasoning (Counting Figures Reasoning), Cubes & Dices, Selection Decision Table (Decision Making)
- Computer Programming: Pseudo Codes, Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Java, Python for Placements by Yash Sir
- DBMS (Computer Science): Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Transaction Management, Concurrency Control, Database Security & Authorization
- SQL (Computer Science): SQL
- OS (Computer Science): Introduction to OS, Process Management, CPU Scheduling, Deadlock, Process Synchronization, Threads & Process Creation, Memory Management, Virtual Memory, File Management
- Computer Networks (Computer Science): 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
- Data Structures (Computer Science): Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
- OOPs (Computer Science): Object Oriented Programming (OOPS)
- Software Engineering (Computer Science): Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
- SVAR Conversational - Spoken English: Communication Assessment
- HR Interview: MR & HR Interview Preparation
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
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.
2:00 – 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.