Arrays

Question 1

What is an array?

Answer 1

Arrays is a data structure consisting of a collection of elements, each identified by a unique index.

• The array can store data of a specified data types
• Array stores data in contiguous cell
• Array size is fixed
• Every cell of an array has a unique index

Arrays can be

• one-dimensional represented in one row with unique index
• two-dimensional represented in [row(s)][column(s)]
• three-dimensional represented in [depth(s)][row(s)][column(s)]
• fourth-(n-dimensional): not used in real world

Use:

• To store multiple of the similar data type of data
• Random access is often

Avoid:

• Data to be stored need to be homogenous
• the limit is not known upfront

Question 2

How is arrays stored in memory?

Answer 2

all dimensional array is stored at the physical level in a contiguous manner starting from the first cell and so on. Each cell will have a unique address assigned at the physical level that will map to a logical level.

i.e. arr = x102; arr will point to the first cell.

Array traversal starts with the first cell accessed by x102 + 0 address and the subsequent cell can be accessed with x102 + 1 and so on.

This is the reason the array needs to start with the 0th index.