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Iteration In Two-Dimensional Array | Arrays
Java Basics
course content

Course Content

Java Basics

Java Basics

1. Getting Started
2. Basic Types, Operations
3. Loops
4. Arrays
5. String

book
Iteration In Two-Dimensional Array

How to Iterate Inside Two-Dimensional Array Using a for-loop?

Iterating through a two-dimensional array can be a bit challenging to grasp initially, so don't worry if it doesn't click right away. In this chapter, I'll demonstrate how to do it and explain how it functions.

We use a nested loop to iterate through a two-dimensional array, meaning one loop inside another. The outer loop iterates over the rows, while the inner loop iterates over the columns. Let's examine the syntax for iterating through a two-dimensional array using the example array we created in the previous chapter:

java

Main

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package com.example; public class Main { public static void main(String[] args) { int[][] twoDimensionalArray = { {1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16} }; for (int i = 0; i < twoDimensionalArray.length; i++) { for (int j = 0; j < twoDimensionalArray[0].length; j++) { System.out.print(twoDimensionalArray[i][j] + " "); } System.out.println(); } } }

Let's delve into the meaning of each element in the code snippet provided above:

  • int[][] twoDimensionalArray = - This line initializes a two-dimensional array;
  • for (int i = 0; i < twoDimensionalArray.length; i++) - The first for-loop iterates over the rows of our matrix. While we're on the first row, our program enters the nested loop, which doesn't impact the outer loop. The variable i represents the current row number;
  • for (int j = 0; j < twoDimensionalArray[0].length; j++) - The second for-loop iterates over the columns of the matrix. While we're on the 0th row, we iterate through the columns of that row. The variable j represents the current column number;
  • System.out.print(twoDimensionalArray[i][j] + " "); - In this line, we use System.out.print to display our values in a single line. Let's see how it operates: while we're on the 0th row, we iterate through the columns on that row. For example, array[0][1], followed by array[0][2], and so on. We continue through the columns as long as j is less than array[0].length. Once we reach array[0].length, we return to the outer array and move to the first row. For example, array[0][3] -> array[1][0]. We've reached our boundaries and then transitioned to row 1.
Task
test

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Your task is to locate and display the diagonal (from the top-left corner to the bottom-right corner) of the provided matrix on the screen:

Note

The diagonal represents a line in the matrix where the row and column numbers are identical.

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Section 4. Chapter 5
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book
Iteration In Two-Dimensional Array

How to Iterate Inside Two-Dimensional Array Using a for-loop?

Iterating through a two-dimensional array can be a bit challenging to grasp initially, so don't worry if it doesn't click right away. In this chapter, I'll demonstrate how to do it and explain how it functions.

We use a nested loop to iterate through a two-dimensional array, meaning one loop inside another. The outer loop iterates over the rows, while the inner loop iterates over the columns. Let's examine the syntax for iterating through a two-dimensional array using the example array we created in the previous chapter:

java

Main

copy
12345678910111213141516
package com.example; public class Main { public static void main(String[] args) { int[][] twoDimensionalArray = { {1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16} }; for (int i = 0; i < twoDimensionalArray.length; i++) { for (int j = 0; j < twoDimensionalArray[0].length; j++) { System.out.print(twoDimensionalArray[i][j] + " "); } System.out.println(); } } }

Let's delve into the meaning of each element in the code snippet provided above:

  • int[][] twoDimensionalArray = - This line initializes a two-dimensional array;
  • for (int i = 0; i < twoDimensionalArray.length; i++) - The first for-loop iterates over the rows of our matrix. While we're on the first row, our program enters the nested loop, which doesn't impact the outer loop. The variable i represents the current row number;
  • for (int j = 0; j < twoDimensionalArray[0].length; j++) - The second for-loop iterates over the columns of the matrix. While we're on the 0th row, we iterate through the columns of that row. The variable j represents the current column number;
  • System.out.print(twoDimensionalArray[i][j] + " "); - In this line, we use System.out.print to display our values in a single line. Let's see how it operates: while we're on the 0th row, we iterate through the columns on that row. For example, array[0][1], followed by array[0][2], and so on. We continue through the columns as long as j is less than array[0].length. Once we reach array[0].length, we return to the outer array and move to the first row. For example, array[0][3] -> array[1][0]. We've reached our boundaries and then transitioned to row 1.
Task
test

Swipe to show code editor

Your task is to locate and display the diagonal (from the top-left corner to the bottom-right corner) of the provided matrix on the screen:

Note

The diagonal represents a line in the matrix where the row and column numbers are identical.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 4. Chapter 5
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