Java -数组

1.一维数组

1.1数组定义

public class Main {public static void main(String[] args) throws Exception {int[] a = new int[10];float[] f = new float[10];double[] d = new double[10];char[] c = new char[10];}
}

1.2 初始化

public class Main {public static void main(String[] args) throws Exception {int[] a = {0, 1, 2};int[] b = new int[3];char[] d = {'a', 'b', 'c'};}
}

 

1.3 访问数组

public class Main {public static void main(String[] args) throws Exception {Scanner sc=new Scanner(System.in);int n=sc.nextInt();int[] a=new int[100];for(int i=0;i<n;i++){a[i]=sc.nextInt();}for(int i=0;i<n;i++){System.out.printf("%d ",a[i]);}}
}

2.多维数组

public class Main {public static void main(String[] args) throws Exception {int[][] a = new int[5][5]; // 大小为5的数组，每个元素是含有5个整数的数组。int[][][] b = new int[1][2][3]; // 大小为1的数组，它的每个元素是含有2个数组的数组// 这些数组的元素是含有3个整数的数组}
}

3.二维数组的遍历

public class Main {public static void main(String[] args) throws Exception {int[][] a = {{4,6,2,8}, {0,7,1,3}, {234,465,12}};for (int[] row: a) {for (int x : row) {System.out.printf("%d ", x);}System.out.println();}}
}

4.常用的API

length：返回数组长度，注意不加小括号
Arrays.sort()：数组排序
Arrays.fill(int[] a, int val)：填充数组
Arrays.toString()：将数组转化为字符串
Arrays.deepToString()：将多维数组转化为字符串