Overview
This lecture is an introduction to a Data Structures and Algorithms course aimed at placement preparation, covering core concepts, prerequisites, and foundational memory management in C/C++.
Course Structure & Prerequisites
- Focuses on topics most relevant for placement and interview preparation.
- The primary programming languages are C and C++, but basic knowledge of Java is also acceptable.
- C is recommended for its “bare bones” approach to data structures and memory.
- Notes and PDF resources will be provided.
What are Data Structures?
- Data structures are ways to arrange data in main (RAM) memory for efficient usage.
- Examples include arrays, linked lists, stacks, queues, graphs, and binary search trees.
- Data structures serve as ingredients for developing efficient algorithms.
What are Algorithms?
- An algorithm is a sequence of steps to solve a given problem.
- Example: Steps to make tea or sort an array (turning [1, 7, 9, 2] into [1, 2, 7, 9]).
- Algorithms can be implemented in C, C++, Java, or Python (but C/C++ is preferred for placements).
Related Concepts: Database, Data Warehouse, Big Data
- Database stores information permanently on disk for fast retrieval, update, and deletion.
- Data warehouse is for managing and analyzing large amounts of "legacy" (older or archived) data.
- Big Data involves specialized techniques for processing extremely large datasets, beyond the scope of this course.
Memory Layout in C Programs
- When a C program runs, code and variables are loaded into RAM.
- Code segment: Holds the program code.
- Static/global segment: Stores static and global variables.
- Stack: Stores local variables and function call information (activation records).
- Each function call creates a new stack frame, which is destroyed when the function returns.
- Heap: Allows dynamic memory allocation during runtime, managed with pointers.
- Memory is allocated using
malloc (C) or new (C++), and must be freed after use to prevent memory leaks.
Stack vs Heap Usage
- Stack is for fixed, short-lived variables tied to function calls.
- Heap is for dynamic, flexible memory allocation, useful when size or lifespan is not known in advance.
- Improper use of heap can cause memory leaks if memory is not freed.
Key Terms & Definitions
- Data Structure — A method to organize data in main memory for efficient operations.
- Algorithm — A step-by-step procedure to solve a specific problem.
- Database — Permanent storage system for efficient data retrieval and modification.
- Data Warehouse — Storage and management of massive, often older, datasets for analysis.
- Big Data — Field dedicated to managing and analyzing extremely large datasets.
- Stack — Memory area managing local variables and function calls.
- Heap — Memory area for dynamically allocated variables.
- Pointer — Variable that stores a memory address, used for dynamic memory management.
- Memory Leak — Failure to properly release heap memory, causing wasted resources.
Action Items / Next Steps
- Review the provided notes and PDF resources.
- Watch the "C++ in One Video" and the 15-hour C tutorial if unfamiliar.
- Prepare for the next lecture on time complexity.