Java不指定长度的二维数组实例

import java.util.*;

public class tek

{

  public static void main(string[] args)

  {

  int [][] a= new int [ 3 ][];

  a[ 0 ]= new int [ 3 ]; //相当于int[] a=new int[3]

  for ( int i= 0 ;i<a[ 0 ].length;i++)

  a[ 0 ][i]=i+ 1 ;

  a[ 1 ]= new int [ 4 ];

  for ( int i= 0 ;i<a[ 1 ].length;i++)

  a[ 1 ][i]=i+ 1 ;

  a[ 2 ]= new int [ 5 ];

  for ( int i= 0 ;i<a[ 2 ].length;i++)

  a[ 2 ][i]=i+ 1 ;

  for ( int i= 0 ;i<a.length;i++)

  {

  for ( int j:a[i])

  system.out.print(j+ " " );

  system.out.println();

  }

  }

}