Stack Practice questions

Duration: 5 min

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Inside: a video lesson and guided study material.

Module outline

  1. HPSC Interview Preparation: Interview Preparation
  2. Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis, DSA using Python
  3. Data Structure & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Sorting Algorithms, Minimum Spanning Trees, Time Complexity Analysis, Graph Theory, Shortest Path Algos
  4. Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security
  5. Computer System & Organisation: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer
  6. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, SQL, File Organization & Indexing, Transaction Management, Concurrency Control
  7. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling
  8. Digital Logic & Circuits: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  9. Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Pushdown Automata & CFG, Turing Machines, Moore & Mealy Machines
  10. 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
  11. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Data Warehousing & Mining
  12. Introduction to Emerging Trends: Emerging Tech Trends
  13. Digital Society & Cyber Law: Society, Law & Ethics
  14. HPSC PGT Previous Year Paper:
  15. HPSC Assistant Professor Previous Year Paper:
  16. Live Sessions: HPSC Live Sessions, EMRS TGT/PGT Live Class
  17. Full Mock Test:
  18. HPSC PGT - MOCK Test Series:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video demonstrates how to trace the execution of a recursive C function to determine its output. The instructor presents a code snippet containing a function named `print(int n)` which includes a base case check `if (n > 4000)`. The function prints the current value of `n`, calls itself recursively with `2*n`, and then prints `n` again. The `main` function initiates this process by calling `print(1000)`. The lecture focuses on manually stepping through the recursion stack to predict the sequence of numbers printed to the console.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins by analyzing the provided C code, specifically the `print` function. He writes `print(1000)` on the whiteboard to represent the initial call from `main`. He evaluates the condition `if (n > 4000)` for `n=1000`, marking it as false. Consequently, the code proceeds to the first `printf("%d ", n)`, which outputs `1000`. He then identifies the next step as a recursive call `print(2*n)`, which becomes `print(2000)`. He starts drawing a tree diagram to visualize the call stack, placing `1000` as the root and `print(2000)` as the child node.

  2. 2:00 – 4:37 02:00-04:37

    Continuing the trace, the instructor evaluates `print(2000)`. The condition `2000 > 4000` is false, so it prints `2000` and calls `print(4000)`. Next, `print(4000)` is evaluated; `4000 > 4000` is false, so it prints `4000` and calls `print(8000)`. The instructor notes that `print(8000)` satisfies the base case `8000 > 4000`, causing the function to return immediately without printing. The execution then unwinds. The second `printf` in `print(4000)` executes, printing `4000`. Then the second `printf` in `print(2000)` executes, printing `2000`. Finally, the second `printf` in `print(1000)` executes, printing `1000`. The final sequence is `1000 2000 4000 4000 2000 1000`, corresponding to option (B).

The lesson effectively illustrates the two-phase nature of recursion: the forward pass where code executes before the recursive call, and the backward pass where code executes after the call returns. By tracing the specific values `1000`, `2000`, `4000`, and the base case `8000`, the instructor demonstrates how the first set of prints creates an ascending sequence while the return phase creates a descending sequence, resulting in a symmetric output pattern.

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