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How to traverse each element in an array in java

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1. Array overview: An array is a container that stores multiple variables (elements). The data types of these multiple variables are the same.

2. Array concept:

Arrays store the same type of data. Data type A container with multiple elements

Arrays can store both basic data types and reference data types

3. Array definition format:

Format 1: Data type [] Array name (commonly used)

Format 2: Data type array name []

4. Array initialization:

  • Arrays in Java must Initialize first before use

  • The so-called initialization is to allocate memory space for the elements in the array and assign a value to each array element.

  • One kind of initialization, the initialization only specifies the length of the group, and the array is assigned an initial value by washing

  • The second type of initialization, the initial value of each element is specified during initialization, and the array length is determined by the system

  • Format: data type [] array name = new data type [array length];

  • The array length is actually the number of elements in the array Number.

- int[] arr = new int[3];

Explanation: A value of type int is defined, and 3 ints can be stored in this array Type of value.

Memory allocation in JAVA

  1. Stack; storage of local variables

  • Local variables are variables defined in methods or statements

  • Local variables are recycled immediately after use


2. Heap: stores new things

  • Every object has a first address value, which is a hexadecimal address

  • The data in each object has a default value

  • After use, it will be recycled by the garbage collector.


3. Method area

4. Common problems with array operations:

-Array index out-of-bounds exception, accessing an index value that does not exist in the array, such as int [ ] arr = new int[2]

This array exists arr[0] arr[1] arr[2]

If you output arr[3], it is an array out of bounds.

  • Null pointer exception, the array reference does not point to the object, but is operating on the elements in the object.

Exercise: Known array int[] arr= {11,22,33,44,55}

Traverse each element in the array.

public class Test05 {

<code>public static void main(String[] args) {	<br>int[] arr = { 11, 22, 33, 44, 55 };	<br>for (int x = 0; x < 5; x++) {

		System.out.println(arr[x]);

	}

}</code>

}

2 .Get the maximum value in the array

Principle of getting the maximum value of the array:

  • First use the first element in the array as a reference

  • Then get all the following elements and compare them with the reference object

  • If any element is larger than the reference object, leave it

  • After all comparisons, the largest element remains.


#public class Test05 {

<code>public static void main(String[] args) {	<br>int[] arr = { 11, 22, 33, 44, 55 };	<br>int max = arr[0];	<br>for (int x = 0; x < arr.length; x++) {		<br>if (max < arr[x]) {			<br>max = arr[x];

		}

	}
	System.out.println(max);
}</code>
}

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