2D Arrays

Examine the following:

double[][] values =

{ {1.2, 9.0, 3.2},

{9.2, 0.5, -1.2},

{7.3, 7.9, 4.8} } ;

what is in values[2][1] ?

• 7.9

• 9.2

• 7.3

• 0.5

Given the following:

double[][] things =

{ {1.2, 9.0, 8.7, 1.0},

{9.2, 0.5, 0.0, 5.2},

{7.3, 7.9, 1.2, 3.9} } ;

What is the value of things.length ?

• 4

• 3

• 12

• 7

Given the following:

long [][] stuff ;

Which of the following statements constructs an array with 5 rows of 7 columns each and assign its reference to stuff ?

• stuff = new stuff[5][7] ;

• stuff = new long[5][7] ;

• stuff = long[5][7] ;

• stuff = long[7][5] ;

int[][] items =

{ {0, 1, 3, 4},

{4, 3, 99, 0},

{3, 2, 7, 70} } ;

• items[ 99 ] = 77;

• items[2][1] = 77;

• items[1][2] = 77;

• items[2][3] = 77;

Which of the following constructs and assigns to array a 2D array with 7 rows, but does not yet construct the rows?

• int[][] array = new int[7];

• int[][] array = new int[][7];

• int[][] array = new int[7][];

• int[] array[7] = new int[];

Given:

int[][] items =

{ {0, 1, 3, 4},

{4, 3, 99, 0},

{3, 2, 7, 70} } ;

Which of the following fragments prints out every element of items?

• for ( int row=0; row < items.length; row++ )

  {

  System.out.println();

  for ( int col=0; col < items.length; col++ )

  System.out.print( items[row][col] + " ");

  }

• for ( int row=0; row < items.length; row++ )

  {

  System.out.println();

  for ( int col=0; col < items[col].length; col++ )

  System.out.print( items[row][col] + " ");

  }

• for ( int row=0; row < items.length; row++ )

  {

  for ( int row=0; row < items[row].length; row++ )

  System.out.print( items[row][col] + " ");

  System.out.println();

  }

• for ( int row=0; row < items.length; row++ )

  {

  System.out.println();

  for ( int col=0; col < items[row].length; col++ )

  System.out.print( items[row][col] + " ");

  }