How to use arr in java

The arr keyword is used to declare a Java array, which is a data structure that stores elements of the same type. Usage includes: using arr to declare an array. Access elements using subscripts. Use a loop to iterate over the array. Use the length property to get the array length. Supports multi-dimensional arrays. Arrays can be initialized or dynamically created, but the size cannot be changed after creation.

Usage of arr in Java

arr is the keyword for declaring an array in Java. An array is a data structure used to store a series of elements of the same type.

Syntax:

数据类型[] 数组名 = {值1, 值2, ..., 值n};

Usage:

1. Declare array

Use the arr keyword to declare an array. For example:

int[] numbers = {1, 2, 3, 4, 5};

2. Access elements

Use array subscripts to access array elements. For example:

int firstNumber = numbers[0]; // 检索第一个元素

3. Loop through the array

Use a for loop to traverse all elements in the array. For example:

for (int number : numbers) {
    System.out.println(number);
}

4. Array length

Use the length attribute to get the length of the array. For example:

int arrayLength = numbers.length;

5. Multidimensional array

Java supports multidimensional arrays. For example, a two-dimensional array can store a matrix.

Syntax:

数据类型[][] 多维数组名 = {{值11, 值12, ..., 值1n}, {值21, 值22, ..., 值2n}, ..., {值m1, 值m2, ..., 值mn}};

6. Initializing the array

In addition to using the initialization list to initialize the array, you can also use the new key Dynamically initialized array of words. For example:

int[] numbers = new int[5]; // 创建一个长度为5的整型数组

Note:

• The size of an array cannot be changed after it is created.
• The index starts from 0, and an out-of-bounds subscript will cause an ArrayIndexOutOfBoundsException exception.

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