Arrays

Overview

In this section we'll be going over using and processing arrays. The array class is a powerful tool that allows us to store multiple values at once and as a result, allows us to return more than one value outside of a method for use.

• Declaring arrays
• Accessing elements
• Foreach loop
• Cloning/Copying
• Passing as arguments
• Returning arrays

New Concepts

Declaring arrays

An array is a group of like-typed variables that are referred to by a common name.Array can contains primitives data types , like integers and strings, as well as objects of a class depending on the definition of array.

An array declaration has two components: the type and the name. type declares the element type of the array.

java ```

public class Main{ int[] numbers = ....;//the type is int, and the name is numbers ... string[] names = ...; }

To **instantiate** an array, we also need to specify the size of the array. So as a recap:First, we must declare a variable of the desired array type. Second, we must allocate the memory that will hold the array, using new, and assign it to the array variable. 

```java
> public class Main{
>  int[] numbers = new int[20];//this int array has a size of 20, meaning it can hold 20 integers
>}

In a situation, where the size of the array and elements of the array are already known, array literals can be used. We essentially list out the array elements without specifying the size

> public class Main{
>  int[] numbers = new int[]{1,2,3,4,5,6,7,8,9,10};//this int array has a size of 10, an the elements are 1-10
>}

Accessing elements

Foreach loop

Cloning/Copying

Passing as arguments

Returning arrays

Activity

Program that asks for user to input data that is then sorted, outputted, and shows the min, the max, the mean, and standard deviation of the set.

Summary

Practice Problems