Unit 8: Lesson 2 - Review Questions

Consider the following method. public static int search(int[][] data, int target){for (int i = 0; i < data.length; i++){for (int j = 0; j < data[i].length; j++){if (data[i][j] == target){return i;}}}return -1;} The following code segment appears in the main method of the same class. What is printed when this code is executed? int[][] mat = {{1, 0, 4, 2, 4},{3, 8, 2, 4, 7}};System.out.println(search(mat, 4));

0

Consider the following code segment. int[][] array = new int[5][5];int u = 1;for (int i = 0; i < array.length; i++) {for (int j = 0; j < array[i].length; j++) {array[i][j] = u;u++;}}System.out.println(array[3][3]); What is printed when this code segment is executed?

19

Suppose data is a 2-d array of Strings that has 5 rows and 5 columns, with initial contents represented by the following table: OOXOOOOXXXOOXOOOOXXXOOXOO Consider the following code segment. for (int i = 0; i < data.length; i++) {for (int j = 0; j < data[i].length; j++) {if (data[i][j].equals("O")) {data[i][j] = "X";} else if (data[i][j].equals("X")) {data[i][j] = "O";}}}for (String[] r : data){for (String s : r){System.out.print(s);}System.out.println();} Which of the following represents what is printed after the code segment is executed?

XXOXX XXOOO XXOXX XXOOO XXOXX

Consider the following method which is intended to return a 1-d array containing the averages of each row in the 2-d array mat. public static double[] getAverages(double[][] mat){double[] avgs = new double[mat.length];for (int i = 0; i < mat.length; i++){/* missing code */}return avgs;} Which of the following should replace /* missing code */ if the method is to work as intended?

double s = 0; for (double n : mat[i]) { s += n; } avgs[i] = s / mat[i].length;