二维数组的声明，定义及应用

二维数组的应用

package Java;
import java.util.Scanner;
public class Domo 
{
	//使用随机数或者键入
	public static void main(String args[])
	{
		//这种声明方式错误，二维数组必须指定第一维的长度或者两个都指明
		//int[][] c = new int[][];
		
		
		//Scanner input = new Scanner(System.in);
		//二维数组的创建
		int[][] a = new int[4][5];
		//创建长度不同的数组
		int[][] b = new int[4][];
		for(int i = 0;i < b.length;i ++)
			b[i] = new int[(int)(Math.random() * 10)];
		//利用Math.random()输入数组元素
		for(int i = 0;i < b.length;i ++)
			for(int j = 0;j < b[i].length;j ++)
				b[i][j] = (int)(Math.random() * 100);
		//输出
		for(int i = 0;i < b.length;i ++)
		{
			for(int j = 0;j < b[i].length;j ++)
				System.out.print(b[i][j] + " ");
			System.out.println();
		}
		
		System.out.println("********************************");
		
		for(int i = 0;i < a.length;i ++)
			for(int j = 0;j < a[i].length;j ++)
				//a[i][j] = input.nextInt();
				a[i][j] = (int)(Math.random() * 100);
		for(int i = 0;i < a.length;i ++)
		{
			for(int j = 0;j < a[i].length;j ++)
				System.out.print(a[i][j] + " ");
			System.out.println();
		}
		
		System.out.println("\nsum of all elements is \n" + sum(a));
	}
	
	public static int sum(int[][] a)
	{
		
		int total = 0;
		for(int i = 0;i < a.length;i ++)
			for(int j = 0;j < a[i].length;j ++)
				total += a[i][j];
		return total;
	}
}