arrays

1. Arrays in C++ – Complete
Conceptual & Practical Guide
• Lecture Title
• Arrays in C++ – Complete Conceptual &
Practical Guide

2. Introduction to Arrays
• What is an Array?
• An array is a collection of elements of the
same data type, stored in contiguous memory
locations, accessed using a single variable
name and an index.
• Why Arrays?
• Without arrays, we would need separate
variables.
• With arrays, we can store multiple values

3. Real-World Motivation
• Examples:
• - Student marks list
• - Temperatures of a week
• - Daily sales records
• - Sensor readings
• - Pixels in an image
• All are same type, sequential, and indexed.

4. Key Characteristics of Arrays
• - Fixed size (static arrays)
• - Same data type
• - Contiguous memory
• - Zero-based indexing
• - Fast access

5. Array Indexing Concept
• Index starts from 0
• int arr[5] = {10, 20, 30, 40, 50};
• arr[0] = 10, arr[1] = 20, arr[2] = 30, arr[3] = 40,
arr[4] = 50

6. Memory Representation of Arrays
• Arrays are stored contiguously in memory.
• If int = 4 bytes, then arr[0], arr[1], arr[2] are
stored 4 bytes apart.

7. Syntax of Array Declaration
• General Syntax:
• data_type array_name[size];
• Examples:
• int numbers[10];
• float prices[5];
• char vowels[6];

8. Array Initialization
• Methods:
• 1. At declaration
• 2. Partial initialization
• 3. Size inference

9. Accessing Array Elements
• Elements are accessed using index:
• cout << arr[0];
• Accessing invalid index causes undefined
behavior.

10. Array Input Using Loop
• Using for loop to input values:
• for(int i=0;i<5;i++) cin >> arr[i];

12. Using Loops with Arrays
• Arrays are commonly used with loops to avoid
repetition and simplify code.

13. Common Array Operations
• Traversal
• Insertion
• Deletion
• Searching
• Sorting
• Updating

14. Traversal Operation
• Visiting each element using loop.
• Time Complexity: O(n)

15. Insertion Operation
• Insertion requires shifting elements to make
space.

16. Deletion Operation
• Deletion requires shifting elements left.

17. Linear Search
• Sequential search.
• Time Complexity: O(n)

18. Types of Arrays
• 1D Array
• 2D Array
• Multi-dimensional Array

19. One-Dimensional Array
• Used for lists and sequential data.

20. Two-Dimensional Array
• Matrix form with rows and columns.

21. 2D Array Traversal
• Nested loops are used for traversal.

22. Memory Layout of 2D Arrays
• Stored in row-major order.

23. Passing Arrays to Functions
• Arrays are passed as pointers.

24. Array vs Variable
• Variable stores single value.
• Array stores multiple values.

25. Limitations of Arrays
• Fixed size
• Wasted memory
• No bounds checking

26. Common Mistakes
• Out of bounds access
• Wrong loop limits

27. Exam Oriented Points
• Index starts from 0
• Contiguous memory
• Fixed size

28. Practice Questions
• Find maximum
• Reverse array
• Matrix addition

29. Mini Class Activity
• Take student marks
• Find total, average, highest, lowest

30. Summary
• Arrays store multiple values of same data
type.

31. What’s Next?
• Vectors
• Dynamic Memory
• Strings
• Pointers & Arrays