Java Array Declaration and Operations

Declaring and Initializing Arrays

• In Java, an array is a fixed-size, homogeneous collection of elements of the same data type.
• Arrays are declared using the [] brackets after the data type.
• Example: int[] myArray; declares an integer array.
• Arrays can be initialized in two ways:
  • Using the new keyword: int[] myArray = new int[5];
  • Using an array initializer: int[] myArray = {1, 2, 3, 4, 5};

Array Operations

• Array elements can be accessed and modified using their index: myArray[0] = 10;
• Arrays have a length property that returns the number of elements: int size = myArray.length;
• Arrays can be copied using the Arrays.copyOf() method: int[] copiedArray = Arrays.copyOf(myArray, myArray.length);

Array Types

• There are two types of arrays in Java:
  • One-dimensional arrays: A single array of elements: int[] myArray = new int[5];
  • Multi-dimensional arrays: An array of arrays: int[][] my2DArray = new int[3][4];

Array Methods

• The Arrays class provides various methods for manipulating arrays:
  • Arrays.sort(): Sorts an array in ascending order.
  • Arrays.binarySearch(): Searches for an element in a sorted array.
  • Arrays.equals(): Checks if two arrays are equal.

Common Array Pitfalls

• ArrayIndexOutOfBoundsException: Thrown when accessing an array element outside its bounds.
• NullPointerException: Thrown when trying to access an array element of a null array.

Declaring and Initializing Arrays

• Arrays are fixed-size, homogeneous collections of elements of the same data type in Java.
• Arrays are declared using the [] brackets after the data type, e.g., int[] myArray;.
• Arrays can be initialized using the new keyword, e.g., int[] myArray = new int[5];, or an array initializer, e.g., int[] myArray = {1, 2, 3, 4, 5};.

Array Operations

• Array elements can be accessed and modified using their index, e.g., myArray[0] = 10;.
• Arrays have a length property that returns the number of elements, e.g., int size = myArray.length;.
• Arrays can be copied using the Arrays.copyOf() method, e.g., int[] copiedArray = Arrays.copyOf(myArray, myArray.length);.

Array Types

• There are two types of arrays in Java: one-dimensional and multi-dimensional arrays.
• One-dimensional arrays are single arrays of elements, e.g., int[] myArray = new int[5];.
• Multi-dimensional arrays are arrays of arrays, e.g., int[][] my2DArray = new int[3][4];.

Array Methods

• The Arrays class provides various methods for manipulating arrays, including:
  • Arrays.sort(): Sorts an array in ascending order.
  • Arrays.binarySearch(): Searches for an element in a sorted array.
  • Arrays.equals(): Checks if two arrays are equal.

Common Array Pitfalls

• ArrayIndexOutOfBoundsException: Thrown when accessing an array element outside its bounds.
• NullPointerException: Thrown when trying to access an array element of a null array.