int a[3][2] = { {123,345},{34,56},{12,78}};则 a[2][1] 的值是()。
A. 34
B. 56
C. 12
D. 78
有如下定义:int[][] arr2 = new int [3][];arr2 [0] = new int [2] ;arr2 [1] = new int [4] ;arr2 [2] = new int [3] ;arr2.length 的值是()
A. 2
B. 3
C. 4
D. 5
有如下定义:int[][] arr2 = new int [3][];arr2 [0] = new int [2] ;arr2 [1] = new int [4] ;arr2 [2] = new int [3] ;arr2[1].length的值是_________。
A. 2
B. 3
C. 4
D. 5
有如下定义:int[][] arr2 = new int [3][];arr2 [0] = new int [2] ;arr2 [1] = new int [4] ;arr2 [2] = new int [3] ;输出该数组所有元素值,代码如下:for (int i = 0 ; i<_________ ; i++){for (int j = 0 ; j< ____________; j++)System.out.println( arr2[i][j]);}空1应该填写 :__________;空2应该填写 :___________;