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Feb 22, 2023

2 pages

How to Use Arrays in Java: Simple Examples & Fun Tricks

Arrays in Java: Declaration, Usage, and Common Algorithms

Arrays are... Show more

Syntax
●
●
Declare & instantiate
●
O datatype [] name = {x,y};
Arrays as objects
●
Declare with length
●
O datatype [] name = new int[5];
●

Advanced Array Operations in Java

This section covers more complex array operations, including element removal, insertion, swapping, and array growth.

Removing an Element

  1. Unordered removal: Replace the element to be removed with the last element of the array.
  2. Ordered removal: Shift all elements after the removed element up by one index. Use a placeholder variable and decrement the size variable.

Example: To remove nums22 in an ordered array, move nums33 to nums22, nums44 to nums33, and so on.

Inserting an Element

  1. Check if there's room in the array.
  2. Move all elements after the intended insertion spot one index higher.
  3. Insert the new element at the desired location.

Highlight: When inserting an element, always ensure there's enough space in the array to avoid ArrayIndexOutOfBoundsException.

Swapping Elements

Use a temporary variable to swap elements using their indices:

int temp = array[i];
array[i] = array[j];
array[j] = temp;

Growing an Array

Since arrays in Java have a fixed size, growing an array requires creating a new, larger array:

  1. Create a new array with the desired larger size.
  2. Loop through the original array, copying all values to the new array.
  3. Assign the new array to the original array variable.

Example:

int[] oldArray = {1, 2, 3};
int[] newArray = new int[oldArray.length * 2];
for (int i = 0; i < oldArray.length; i++) {
    newArray[i] = oldArray[i];
}
oldArray = newArray;

Vocabulary: Array growth - The process of creating a new, larger array and copying elements from the old array to accommodate more elements.

These advanced operations are crucial for efficient array manipulation in Java, enabling developers to perform complex data management tasks within their applications.

Syntax
●
●
Declare & instantiate
●
O datatype [] name = {x,y};
Arrays as objects
●
Declare with length
●
O datatype [] name = new int[5];
●

Arrays in Java: Declaration and Initialization

Arrays in Java are objects that store multiple values of the same data type. They offer efficient ways to handle collections of data.

Definition: An array is a fixed-size, ordered collection of elements of the same data type.

Declaring and Instantiating Arrays

There are multiple ways to declare and instantiate arrays in Java:

  1. Declare and initialize in one line: datatype[] name = {x, y, z}; Example: int[] nums = {2, 4, 6};
  2. Declare with a specific length: datatype[] name = new datatypelengthlength; Example: int[] nums = new int55;

Highlight: Arrays in Java are objects, not primitive types.

Array Properties

  • Common array types include int[], double[], and String[].
  • Arrays can also store custom objects, e.g., Car[] cars = {car1, car2};
  • Array indices start at 0 and end at length - 1.
  • To get the length of an array, use arrayName.length.
  • You can modify elements in an array, but not its length after initialization.
  • Arrays can be used as parameter values and return values in methods.
  • Arrays can be partially filled.

Vocabulary: Object reference - When you set one array equal to another, it creates a reference to the same object in memory.

Common Algorithms for Array Manipulation

  1. Target Search: Use a loop and conditional statement. Check if numsxx is the target and save the index.
  2. Accumulation: Initialize a sum variable. Loop through the array, incrementing the index and adding numsxx to the sum.
  3. Finding Maximum/Minimum: Initialize a max/min variable with the first element of the array. Loop through, comparing each element to the current max/min and updating if necessary.
  4. Checking for Increasing or Decreasing Order: Use a loop and conditional statement. Ensure the loop length only goes up to length - 1 to avoid Out Of Bounds errors. Compare numsxx with numsx+1x+1 to check for increasing or decreasing order.


Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.9/5

App Store

4.8/5

Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user

 

AP Computer Science A

67

Feb 22, 2023

2 pages

How to Use Arrays in Java: Simple Examples & Fun Tricks

Arrays in Java: Declaration, Usage, and Common Algorithms

Arrays are fundamental data structures in Java, used to store multiple elements of the same type. This guide covers array declaration, initialization, and common algorithms for array manipulation.

Bold keywords: Array... Show more

Syntax
●
●
Declare & instantiate
●
O datatype [] name = {x,y};
Arrays as objects
●
Declare with length
●
O datatype [] name = new int[5];
●

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Advanced Array Operations in Java

This section covers more complex array operations, including element removal, insertion, swapping, and array growth.

Removing an Element

  1. Unordered removal: Replace the element to be removed with the last element of the array.
  2. Ordered removal: Shift all elements after the removed element up by one index. Use a placeholder variable and decrement the size variable.

Example: To remove nums22 in an ordered array, move nums33 to nums22, nums44 to nums33, and so on.

Inserting an Element

  1. Check if there's room in the array.
  2. Move all elements after the intended insertion spot one index higher.
  3. Insert the new element at the desired location.

Highlight: When inserting an element, always ensure there's enough space in the array to avoid ArrayIndexOutOfBoundsException.

Swapping Elements

Use a temporary variable to swap elements using their indices:

int temp = array[i];
array[i] = array[j];
array[j] = temp;

Growing an Array

Since arrays in Java have a fixed size, growing an array requires creating a new, larger array:

  1. Create a new array with the desired larger size.
  2. Loop through the original array, copying all values to the new array.
  3. Assign the new array to the original array variable.

Example:

int[] oldArray = {1, 2, 3};
int[] newArray = new int[oldArray.length * 2];
for (int i = 0; i < oldArray.length; i++) {
    newArray[i] = oldArray[i];
}
oldArray = newArray;

Vocabulary: Array growth - The process of creating a new, larger array and copying elements from the old array to accommodate more elements.

These advanced operations are crucial for efficient array manipulation in Java, enabling developers to perform complex data management tasks within their applications.

Syntax
●
●
Declare & instantiate
●
O datatype [] name = {x,y};
Arrays as objects
●
Declare with length
●
O datatype [] name = new int[5];
●

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Arrays in Java: Declaration and Initialization

Arrays in Java are objects that store multiple values of the same data type. They offer efficient ways to handle collections of data.

Definition: An array is a fixed-size, ordered collection of elements of the same data type.

Declaring and Instantiating Arrays

There are multiple ways to declare and instantiate arrays in Java:

  1. Declare and initialize in one line: datatype[] name = {x, y, z}; Example: int[] nums = {2, 4, 6};
  2. Declare with a specific length: datatype[] name = new datatypelengthlength; Example: int[] nums = new int55;

Highlight: Arrays in Java are objects, not primitive types.

Array Properties

  • Common array types include int[], double[], and String[].
  • Arrays can also store custom objects, e.g., Car[] cars = {car1, car2};
  • Array indices start at 0 and end at length - 1.
  • To get the length of an array, use arrayName.length.
  • You can modify elements in an array, but not its length after initialization.
  • Arrays can be used as parameter values and return values in methods.
  • Arrays can be partially filled.

Vocabulary: Object reference - When you set one array equal to another, it creates a reference to the same object in memory.

Common Algorithms for Array Manipulation

  1. Target Search: Use a loop and conditional statement. Check if numsxx is the target and save the index.
  2. Accumulation: Initialize a sum variable. Loop through the array, incrementing the index and adding numsxx to the sum.
  3. Finding Maximum/Minimum: Initialize a max/min variable with the first element of the array. Loop through, comparing each element to the current max/min and updating if necessary.
  4. Checking for Increasing or Decreasing Order: Use a loop and conditional statement. Ensure the loop length only goes up to length - 1 to avoid Out Of Bounds errors. Compare numsxx with numsx+1x+1 to check for increasing or decreasing order.

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.9/5

App Store

4.8/5

Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️

Thomas R

iOS user

Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades

Brad T

Android user

Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend

Aubrey

iOS user

Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀

Marco B

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!

Paul T

iOS user