An array is a collection of data types that holds a fixed number of values of the same type. Arrays are declared with a data type, name, and size. They store elements in consecutive memory locations that can be accessed via an index. The length of an array is calculated as the upper bound index minus the lower bound plus one. Arrays can be one-dimensional, two-dimensional in the form of a matrix, or three-dimensional with additional indices.

2. CONTENT

3. Array
 Collection of data types
 Holds a fixed numbers of values
 Values are of common type

4. Example
 If we want to store marks of 5 students, we can create an array for this,
int marks[5];
0 1 2 3 4

5. Declaration of an Array
To Declare an array following three things are specified –
 Data types – int, char, float, double
 Name – to identify an array
 Size – Max number of values that array holds
 Index must be written in square brackets [ ]
 Note – array is declared before using it in a program.

6. Syntax
 Data type array name[array_size]
Example –
int marks[5]
char num[6]
float num[2]

7. Creating arrays
 The array index starts from zero
 The last element will be (n-1) considering “n” number of elements
Example - To insert five numbers
int num[5]
1st element 2nd element 3rd element 4th element 5th element
[0] [1] [2] [3] [4]

8. Address of array elements
 Data elements of arrays are stored in consecutive memory locations
 Storing base address of 1st elements in array is sufficient to calculate
address
Formula: Address, A[k] = Base address (A) + w(k-lower_bound)
Word size

9. Example
 Given array int marks[4] = { 8,7,9,6}
 Calculate address of marks[3]
 If base address is 100
8 7 9 6
[0] [1] [2] [3]
100 102 104 106
marks
Base address
A[k] = Base address (A) + w(k-lower_bound)
Word size

10. Length of the array
 Length of array is given by the no. of elements stored in it.
 Formula –
length= Upper_bound – Lower_bound +1
• Upper_bound – index of last element
• Lower_bound - index of first element in array

11. example
 Let marks be an array of integer are
marks[0] = 8, marks[1] = 4, marks[2] = 9, marks[3] = 8, marks[4] = 6
 Memory representation
Length = Upper_bound – Lower_bound +1
Length = 4 – 0 + 1 = 5
8 7 9 6
[0] [1] [2] [3] [4]
6

12. Types of array
One- dimensional array
Two- dimensional array
Three- dimensional array

13. One dimensional array
 An array which has only one subscript is known as
one dimensional array.

15. Two dimensional arrays
 Represents the list of items using two index.
 The two dimensional (2D) array in c programming is also
known as matrix.

17. Three-dimensional array
 A 3D array adds another dimension, turning it into an
array of array of arrays.

18. CONCLUSION
• An array is used to represent a
collection of objects or values, whose
length you know ahead of time.

19. REFERENCES
• WIKIPEDIA
• QUORA
• OVER IQ
• YOU TUBE