External Storage Class

Duration: 3 min

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Module outline

  1. About the course: About the Course
  2. Mathematical Aptitude: Number System, HCF LCM, Divisibility Rules, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Time and Work, Mensuration and Geometry, Simple Interest and Compound Interest, Speed Time and Distance, Age Problems, Mixture and Alligation, Algebra, Powers and Exponents (Surds and Indices), Pipe and Cistern, Trigonometry, Statistics, Data Interpretation, Arithmetic
  3. Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Analogy, Blood Relations, Directions (Direction Test), Ranking, Order and Sequence, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Seating Arrangements, Syllogisms, Venn Diagram, Puzzle Solving (Puzzles), Logical Sequence Of Words, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Analytical Reasoning (Counting Figures Reasoning), Cubes & Dices, Calendar, Clock
  4. General Knowledge: Physics, Chemistry, Biology, History, Geography, Polity, Indian Economy, GK- Current Affairs, Static General Knowledge
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  6. Environmental Science: Environment
  7. Unit 1 | Digital Electronics: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  8. Unit 2 | COA: Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Control Unit Design, Register Transfer and Microoperations, Programming the Basic Computer
  9. Unit 3 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  10. Unit 3 | Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  11. Unit 4 | Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  12. Unit 5 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management
  13. Unit 6 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Transaction Management, Concurrency Control
  14. Unit 7 | 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
  15. Unit 8 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  16. Unit 9 | Object Oriented Programming: OOPS with C++
  17. Unit 10 | Web Development: HTML Basics, CSS, JavaScript-Basics, XML
  18. Unit 11 | Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines
  19. Unit 12 | IoT: Emerging Tech Trends, Cloud Computing
  20. Unit 13 | Artificial Intelligence: Approaches to AI, Search Algorithms, Game Playing, Knowledge Representation, Natural Language Processing, Artificial Neural Networks, Genetic Algorithms
  21. Unit 14 | E-Commerce: Electronic Data Interchange and E-Commerce, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Physical Security and Cryptography Basics, Cyber Safety and Security
  22. Unit 15 | Multimedia: Multimedia
  23. Unit 16 | Python: 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
  24. Full Length Mock Tests — General Paper:
  25. Full Length Mock Tests — Computer Science (Paper II):
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture introduces the external storage class in C programming, detailing its characteristics through a structured table and practical code examples. The instructor explains that external variables have a default initial value of zero, global scope, and a lifetime extending throughout the entire program execution. A C code snippet demonstrates how an external variable `i` is shared between the main function and helper functions like increment() and decrement(), illustrating that modifications in one function affect others due to global visibility. The lesson further clarifies scope conflicts where local variables take precedence over globals and introduces static variables declared outside functions, which share external behavior but are file-scoped. Finally, the video concludes by discussing the rationale behind C's storage classes, emphasizing that programmers should choose them to economize memory space and improve execution speed.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The lecture begins by defining the external storage class using a table that lists three key features: default initial value, scope, and life. On-screen text explicitly states the default initial value is Zero, the scope is Global, and the life lasts as long as program execution continues. The instructor uses red underlines to emphasize 'Global' and a checkmark next to 'Zero'. A C code example is then introduced showing an external variable `int i = 1;` declared outside the main function. This code demonstrates how functions like increment() and decrement() access this shared variable, proving that external variables maintain state across function calls.

  2. 2:00 – 2:56 02:00-02:56

    The instructor transitions to discussing variable scope conflicts, explaining that if a local and global variable share the same name, the local variable takes precedence. The slide shows code where `printf` accesses a variable defined in two places, highlighting this shadowing behavior. The lesson then introduces static variables declared outside functions, noting they act like external variables but are limited in scope to the file where defined. The segment concludes with a slide titled 'Which to Use When', which states that Dennis Ritchie provided storage classes so programmers could decide based on two goals: to economize memory space and improve the speed of execution.

The video provides a foundational overview of C storage classes, specifically focusing on the external class. It establishes that external variables are initialized to zero by default and possess global scope, meaning they are accessible from any function within the program. The practical demonstration using `int i = 1;` outside main() effectively shows how this scope allows multiple functions to modify and access the same memory location. The lecture also touches on related concepts like static variables, which offer file-level scope similar to external variables but with different linkage properties. The final section contextualizes these technical details within the broader design philosophy of C, where storage classes are tools for memory optimization and performance tuning rather than rigid rules.

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