Java OCA OCP Practice Question 1848

Question

Given the following code : 

public class Main  {

    int [][] matrix = new int [2][3];

    int a [] =  {1, 2, 3};
    int b [] =  {4, 5, 6};

    public int compute (int x, int y){
        //1  : Insert Line of Code here
     }/*w  w  w .  j  av  a2  s  . c o m*/

    public void loadMatrix (){
        for (int x=0; x<matrix .length; x++){
            for (int y=0; y<matrix [x].length; y++){
                //2: Insert Line of Code here
             }
         }
     }
}

What can be inserted at // 1 and //2?

Select 1 option 

A. return a (x)*b (y);
   and// w  w w.j  a v a  2s. c om
   matrix (x, y) = compute (x, y);

B. return a [x]*b [y];
   and
   matrix [x, y] = compute (x, y); C. return a [x]*b [y];
   and
   matrix [x][y] = compute (x, y);

D. return a (x)*b (y);
   and
   matrix (x)(y) = compute (x, y);

E. return a [x]*b [y];
   and
   matrix [[x][y]] = compute (x, y);



Correct Option is  : C

Note

The correct syntax to access any element within an array is to use the square brackets - [].

Thus, to access the first element in an array, you would use array[0].

For a multi dimensional array, to reach an individual item, you need to specify index for each dimension.

Since matrix is a two dimensional array, matrix is an array of array and matrix[0] will give you the first array of the arrays.

matrix[0][0] will give you the first element of the first array of the arrays.




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