Java 多维数组的完整指南。数组是同质数据多维结构，是具有相似数据类型的元素的集合。它们存储在连续的内存位置中。在数组中，第一个元素存储在索引 0 中；第二个元素存储在索引 1 中，依此类推。数组可以是单维或多维的。在本文档中，我们将研究 Java 中的多维数组。多维数组是可以容纳多个行和列的数组的数组。现在，让我们在以下部分中了解多维数组的语法和实现。
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data_type[dimension 1][dimension 2][]…[dimension n] array_name= new data_type[size 1][size 2]…[size n]
Java 中最常见的多维数组是：
二维数组通常用于超级马里奥等平台视频游戏中来表示地形或屏幕。它们还可以用于绘制棋盘、表示电子表格等结构。
代码：
int[][] array1 = new int[2][2];//Two dimensional Integer Array with 2 rows and 2 columns
示例：
9 10
7 66
这是一个两行两列的二维数组。
三维数组在实时应用程序中并不常用。因此，在编程示例中也更倾向于二维数组。
代码：
int[][][] array2 = new int[12][24][36]; //Three dimensional Array
示例：
6 8 66
66 65 47
46 89 98
如果知道普通数组，就很容易理解 Java 中的多维数组。多维数组可以如下声明：
首先让我们看一下二维数组的声明：
确保在 Java 编程时创建正确的声明。
代码：
//Java Program to demonstrate the multidimensional 2D array
public class MultidimensionalArray {
public static void main(String args[]){
//2D array a is declared and initialized
int a[][]={{2,2,3},{8,4,5},{9,4,5}};
//Print the array elements
for(int i=0;i<3;i++){
for(int j=0;j<3;j++){
System.out.print(a[i][j]+" ");
}
System.out.println();
}
}}输出：
三维数组的声明可以讨论。
这些数组可以是任何数据类型。以下是一些具有不同数据类型的三维数组。
代码：
//Java Program to demonstrate the multidimensional array
public class MultidimensionalArray {
//main method
public static void main(String[] args) {
//3D array arr
int[][][] arr = { { { 1 , -9 , 3 } ,{ 2 , 7 , 4 } } , { { -45 , -5 , 6 , 75 } , { 88 } , { 29 , 30 } } };
// for..each loop to iterate through the elements of the 3d array arr
for (int[][] ar: arr) {
for (int[] a: ar) {
for(int finalarray: a) {
System.out.println(finalarray);
}
}
}
}
}输出：
多维数组可以通过多种方式初始化：
In a more traditional way, Initializing Array elements can be as follows.
int[][][] a = { { { 11 , 23 , 30 }, { 5 ,65 , 70 } , { 0 , 80 , 10 } ,{ 10 , 12 , 450 } } ,{ { 33 , 2 , 4 } , {11, 66, 6}, {55, 11, 22}, {11, 57, 43} } };In this case, even though the size of rows and columns are not mentioned, the java compiler is able to identify the size of rows and columns by counting the number of elements.
In the case of storing a large number of elements, Nested For Loop can be used as shown below:
int i, j, k;
for(i = 0; i < 2; i++) {
for(j = 0; j < 3; j++) {
for(k = 0; k < 4; k++) {
a[i][j][k] = i + j + k;} } }int a= new int[3][2][4]; a[0][2][1]= 33; a[0][1][2]= 73; a[0][1][1]= 88;
A three-dimensional array of size 3 levels * 2 rows * 4 columns is created, but values are assigned to some positions only. Since none of the other elements does have any value assigned, default values will be assigned.
Multidimensional Array in Java can perform several operations.
Let Us See the Matrix Addition of Two Arrays.
Code:
import java.util.*;
//Java Program to demonstrate the multidimensional array
public class MultidimensionalArray {
//main method
public static void main(String args[])
{
int row, col, c, d;
//input the number of rows and columns
Scanner <u>in</u> = new Scanner(System.in);
System.out.println("Enter the number of rows of matrix");
row = in.nextInt();
System.out.println("Enter the number of columns of matrix");
col = in.nextInt();
//initialization of two matrices and sum matrix
int firstmat[][] = new int[row][col];
int secondmat[][] = new int[row][col];
int summat[][] = new int[row][col];
//adding elements to first matrix
System.out.println("Enter the elements to be added to the first matrix");
for (c = 0; c < row; c++)
for (d = 0; d < col; d++)
firstmat[c][d] = in.nextInt();
//adding elements to second matrix
System.out.println("Enter the elements to be added to the second matrix");
for (c = 0 ; c < row ; c++)
for (d = 0 ; d < col ; d++)
secondmat[c][d] = in.nextInt();
//sum of the two matrices
for (c = 0; c < row; c++)
for (d = 0; d < col; d++)
summat[c][d] = firstmat[c][d] + secondmat[c][d];
System.out.println("Sum of the two given matrices is:");
//printing the sum matrix
for (c = 0; c < row; c++)
{
for (d = 0; d < col; d++)
System.out.print(summat[c][d]+"\t");
System.out.println();
}
}
}Output:
If subtraction needs to be performed, replace ‘+’ with ‘-‘ in the code.
Let us see how Matrix Multiplication Works.
Code:
import java.util.*;
//Java Program to perform matrix multiplication
public class MultidimensionalArray {
//main method
static int N = 4;
// multiply matrices a and b, and then stores the result in c
static void mul(int a[][],
int b[][], int c[][])
{
int i, j, k;
for (i = 0; i < N; i++)
{
for (j = 0; j < N; j++)
{
c[i][j] = 0;
for (k = 0; k < N; k++)
c[i][j] += a[i][k] * b[k][j]; //multiply a and b matrices
}
}
}
//main method
public static void main (String[] args)
{
int a[][] = { {9, 7, 2, 3},
{9, 7, 2, 3},
{4, 13, 32, 2},
{9, 7, 2, 3}};
int b[][] = {{ 9, 7, 2, 3}, {9, 7, 2, 3},
{9, 7, 2, 3},
{4, 13, 32, 2}};
// Store the result in c
int c[][] = new int[N][N] ;
int i, j;
mul(a, b, c); //calling the mul method
System.out.println("Multiplication result matrix" + " is ");
for (i = 0; i < N; i++)
{
for (j = 0; j < N; j++)
System.out.print( c[i][j] + " ");
System.out.println();
}
}
}Output:
Arrays are homogenous data structures that can store similar types of elements. It can be of single-dimensional or multidimensional. In this document, multidimensional arrays are discussed with explaining the syntax structure, initialization, etc.
This is a guide to Multidimensional Array in Java. Here we discuss 2 types of the multidimensional array in java, how to declare, how to initialize and operation in it. You can also go through our other related articles to learn more –
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