Tree Traversal Pseudocode (Pre-order)

Duration: 8 min

This video lesson is available to enrolled students.

Return to /learn/UP-LT-GRADE-ASSISTANT-TEACHER-2025/cs-03-data-structures-and-algorithm/tree/traversals-construction/asset-tree-traversal-pseudocode-pre-order after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. CS | 01 | Digital Logic and Circuits and Discrete Mathematical Structures: Digital Systems & Boolean Basics, Number System, Number Representation, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Permutation and Combination
  3. CS | 02 | Computer Organization and Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Multiprocessors
  4. CS | 03 | Data Structures and Algorithm: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Complexity Theory, Advanced Algorithms
  5. CS | 04 | Problem Solving through C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  6. CS | 05 | Object Oriented Techniques: Object Oriented Technology, Java
  7. CS | 06 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Unix OS
  8. CS | 07 | Database Management Systems: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Database Security & Authorization, Query Processing & Optimization, File Organization & Indexing
  9. CS | 08 | 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
  10. CS | 09 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  11. CS | 10 | Internet Technology, Web Design and Web Technology: Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, JavaScript-Basics, HTML Basics
  12. CS | 11 | System Analysis And Design: Fundamentals of Systems and Information Systems, SDLC and Development Approaches, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Security, Risk Management & Maintenance
  13. CS | 12 | Information Security and Cyber Laws: Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Electronic Data Interchange and E-Commerce, Physical Security and Cryptography Basics, Intrusion Detection Systems (IDS), Cyber Safety and Security
  14. CS | 13 | Computer Graphics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing
  15. GS Paper | 01 | Indian and World Geography: Geography
  16. GS Paper | 02 | History: History
  17. GS Paper | 03 | Indian Economy & Social Development: Indian Economy
  18. GS Paper | 04 | General Science: Biology, Chemistry, Physics
  19. GS Paper | 05 | Elementary Maths: Number System, Divisibility Rules, HCF LCM, Percentage, Profit and Loss, Simple Interest and Compound Interest, Ratio and Proportion (Ratios), Average, Time and Work, Speed Time and Distance, Algebra, Mensuration and Geometry, Data Interpretation, Arithmetic, Statistics, Probability, Sequence and Series (Series), Mixture and Alligation, Calculus, Trigonometry, Vectors
  20. GS Paper | 06 | Indian Polity and Governance: Polity
  21. GS Paper | 07 | Current Events: GK- Current Affairs
  22. UPLT Live Classes Notes: UPLT Live Classes
  23. UPLT Full Mock Tests Tier 1:
  24. UPLT Full Mock Tests Tier 2:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture provides a detailed analysis of a C function named `what` designed to traverse a binary tree. The instructor begins by presenting the code snippet, which takes a pointer to a binary tree node (`struct Bnode *t`) as an argument. He explains the logic flow, highlighting the base case check `if (t)` and the three operations performed within the block: printing the node's data, recursively calling the function on the left child (`LC`), and then on the right child (`RC`). To illustrate the function's behavior, the instructor draws a sample binary tree with the root node 10, left child 20, right child 30, and further children 40 and 50 under node 20. He then manually traces the execution of the function on this tree, writing down the sequence of recursive calls. Finally, he deduces the output sequence (10, 20, 40, 50, 30) and identifies the traversal method as Preorder Traversal.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video begins with a clear display of the C code snippet `void what(struct Bnode *t)`. The instructor uses a digital pen to underline the function name `what` and the parameter `t`, emphasizing that this is a recursive function operating on a binary tree node structure. He explains the `if (t)` condition, which serves as the termination condition for the recursion, ensuring the function stops when it reaches a null pointer. He then points to the three lines inside the `if` block: `printf("%d', t->data);`, `what(t->LC);`, and `what(t->RC);`. He highlights the specific order of these operations, noting that the data is printed first, followed by the recursive call to the left child, and finally the right child.

  2. 2:00 – 5:00 02:00-05:00

    To visualize the function's behavior, the instructor draws a binary tree on the right side of the screen. The tree has a root node with value 10. The left child of 10 is 20, and the right child is 30. Node 20 further has a left child 40 and a right child 50. He starts the execution trace by writing `what(10)` on the board. He explains that since 10 is not null, the function prints 10. Then, it recursively calls `what` on the left child, which is 20. He writes `what(20)` below `what(10)`. He continues this process, writing `what(40)` as the next recursive call on the left child of 20.

  3. 5:00 – 7:47 05:00-07:47

    The instructor completes the trace by writing `what(50)` for the right child of 20. After finishing the left subtree of the root, he traces the right child of 10, writing `what(30)`. He then compiles the final output sequence based on the order of `printf` statements: 10, 20, 40, 50, 30. He writes "preorder" underneath the sequence to explicitly name the traversal type. He concludes that the function performs a Preorder Traversal because it visits the root node before its children.

The lecture effectively demonstrates how to analyze recursive tree traversal functions. By breaking down the code into its constituent parts (base case, processing, recursion) and applying it to a concrete example, the instructor clarifies the concept of Preorder Traversal. The visual tracing of the call stack and the resulting output sequence provides a clear understanding of the 'Root-Left-Right' order characteristic of this traversal method. This step-by-step approach helps students understand how recursive calls are managed and how the final output is generated based on the order of operations in the code.

Loading lesson…