2D Array Column Major Implementation

Duration: 5 min

This video lesson is available to enrolled students.

Return to /learn/COGNIZANT-PREPARATION/data-structures/array/1d-2d-addressing/asset-2d-array-column-major-implementation after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. Communication Round: Vocabulary, Subject Verb Agreement (Verb Noun Agreement), Tenses, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Cloze Test (Cloze Passage), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Direct and Indirect Speech, Active Passive Voice (Voice), Verbal Analogy (Word Based Analogy), Articles, Preposition, Conjunction, Sentence Construction, English Writing Ability, Communication Assessment
  2. Quantitative Aptitude: Ratio and Proportion (Ratios), Divisibility Rules, Data Interpretation, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Speed Time and Distance, Percentage, Average, Powers and Exponents (Surds and Indices), Time and Work, Mensuration and Geometry, Age Problems, Pipe and Cistern, Probability, Profit and Loss, Simple Interest and Compound Interest, Algebra
  3. Analytical and Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Directions (Direction Test), Ranking, Order and Sequence, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Logical Sequence Of Words, Puzzle Solving (Puzzles), Syllogisms, Seating Arrangements, Calendar, Clock, Blood Relations, Cubes & Dices, Venn Diagram, Analytical Reasoning (Counting Figures Reasoning)
  4. Cognizant Gaming Aptitude: Gamified / Game Based Aptitude
  5. Java (Cluster 1): Java
  6. ANSI SQL MySQL (Cluster 1,2,3): SQL
  7. HTML, CSS, JavaScript (Cluster 1,3): HTML, CSS, JavaScript
  8. Python (Cluster 2): Python for Placements by Yash Sir
  9. Cloud Fundamentals (Cluster 2): Emerging Tech Trends
  10. C# (Cluster 3): C#
  11. OOPs: Object Oriented Programming (OOPS)
  12. Technical Assessment (Coding): Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Pseudo Codes
  13. Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  14. DBMS: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, ORDBMS, Database Security & Authorization, Query Processing & Optimization, Enhanced Data Models, Data Warehousing & Mining, Big Data Systems, NoSQL
  15. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Linux OS, Security, Distributed Systems, Virtual Machines
  16. 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, Mobile Technology, Cloud Computing and IoT, Cyber and Info Security
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture explains the Column Major implementation of 2D arrays in computer memory. It begins by defining the storage order where elements are arranged sequentially column by column. The instructor uses a visual 3x3 matrix example to demonstrate how memory locations are allocated, starting with the first column, followed by the second, and so on. The second half of the lecture focuses on deriving the mathematical formula to calculate the memory address of any specific element a[i][j] within this storage scheme. Key variables such as base address, element size, and row/column bounds are defined to construct the final address calculation equation. This dual approach of visualization and formula derivation provides a comprehensive understanding of the topic.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the concept of Column Major order using a 3x3 matrix labeled with indices from 0,0 to 2,2. He visually demonstrates the storage sequence by highlighting the first column (0,0, 1,0, 2,0) in red, the second column (0,1, 1,1, 2,1) in green, and the third column (0,2, 1,2, 2,2) in blue. He draws red diagonal lines through the columns to emphasize that the entire first column is stored first, followed by the second, and then the third. This visual aid corresponds to the linear memory layout shown below the matrix, where the sequence is 0,0, 1,0, 2,0, 0,1, 1,1, 2,1, 0,2, 1,2, 2,2. The instructor explicitly states that elements of the first column occupy the first set of memory locations, the second column occupies the next set, and so on.

  2. 2:00 – 4:45 02:00-04:45

    The lecture transitions to deriving the address calculation formula. The instructor defines variables on the screen: B for Base address, W for Size of each element, L1 and U1 for Lower and Upper bounds of rows, and L2 and U2 for Lower and Upper bounds of columns. He draws a generic 4x4 grid to generalize the concept beyond the 3x3 example. He writes the formula Address of a[i][j] = B + W * [(j - L2) * (U1 - L1 + 1) + (i - L1)] on the whiteboard. He breaks down the formula components, explaining that (U1 - L1 + 1) represents the total number of rows, (j - L2) is the number of columns preceding the current column, and (i - L1) accounts for the elements before the target in the current column. He emphasizes that the term (j - L2) * (U1 - L1 + 1) calculates the total elements in all previous columns.

The video effectively bridges the gap between conceptual understanding and mathematical application. By first visualizing the storage order with a concrete 3x3 example, the instructor makes the abstract concept of column-major storage tangible. He then systematically derives the address formula, defining every variable clearly. This progression ensures students understand not just how the data is stored, but how to calculate the exact memory location of any element, which is crucial for low-level programming and memory management tasks. The clear distinction between row-major and column-major logic is established through these visual and algebraic steps.

Loading lesson…