Two-Dimensional Arrays in Java

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A two-dimensional array in Java is an array of arrays. It is used to store data in a row and column format, similar to a table or matrix.

Two-dimensional arrays are commonly used in applications such as matrices, game boards, and tabular data processing.

A two-dimensional array consists of rows and columns. Each element is accessed using two indexes: one for the row and one for the column.

Example explanation: If an array has 3 rows and 4 columns, valid indexes are from [0][0] to [2][3].

Rows and columns are zero-indexed in Java.

Declaring a two-dimensional array specifies the data type and reference variable.

Two-dimensional arrays can be initialized in different ways.

Once defined, the number of rows is fixed, but column sizes can vary in jagged arrays.

Elements are accessed using both row and column indexes.

Invalid row or column indexes result in ArrayIndexOutOfBoundsException.

Traversal is usually done using nested loops.

Use array.length for rows and array[i].length for columns.

A jagged array is a two-dimensional array where each row can have a different number of columns.

Jagged arrays help optimize memory when data size varies per row.

Two-Dimensional Arrays in Java

Question 1 of 5

Depends on size

medium

Create a 2D array representing a 3×3 matrix and print it.
Write a program to find the sum of all elements in a two-dimensional array.
Find the transpose of a matrix using a two-dimensional array.
Create a jagged array to store marks of students in different subjects.
Explain the difference between a rectangular array and a jagged array with examples.