Question

Question 1)

Suppose a program has the following code:

const int X = 2, Y = 3;

int sum;

int values[X][Y] = {{1, 2, 3},

                                 {4, 5, 6}};

for(int i=0; i<X; i++)

{

     sum=0;

     for(int j=0; j<Y; j++)

        sum+=values[i][j];

   cout<<sum<<endl;

}

What is this program getting the sum of?

Group of answer choices

D-) The columns of the 2D array

C-) The rows of the 2D array

A-) All of the elements of the 2D array

B-) The diagonals of the 2D array

Question 2

In the game of tic-tac-toe, two players (‘X’ and ‘O’) play against each other on a 3X3 (three by three) grid with 9 (nine) squares. There are three ways to win the game:

• Get three of your symbol (‘X’ or ‘O’) in a row
• Get three of your symbol (‘X’ or ‘O’) in a column
• Get three of your symbol (‘X’ or ‘O’) diagonally

For example, if the current state of the game is:

O	X	O
	X
	X	O

Then player X has won because they got three X’s in a column.

Like many board games, the game of tic-tac-toe can be represented by a 2D array. Suppose the game board is represented by a 2D array named arr of type char (each index stores ‘X’ or ‘O’). To determine if a player has won the game, there are several cases that have to be checked. Which of the options below correctly determines if player X has won the game by getting three X’s in a column?

Group of answer choices

A)

if((arr[0][0] == ‘X’ || arr[0][1] == ‘X’ || arr[0][2] == ‘X’) &&

   (arr[1][0] == ‘X’ || arr[1][1] == ‘X’ || arr[1][2] == ‘X’) &&

  (arr[2][0] == ‘X’ || arr[2][1] == ‘X’ || arr[2][2] == ‘X’))

                                 cout<<”Player X has won by getting three X’s in a column”;

B)

if((arr[0][0] == ‘X’ && arr[0][1] == ‘X’ && arr[0][2] == ‘X’) ||

   (arr[1][0] == ‘X’ && arr[1][1] == ‘X’ && arr[1][2] == ‘X’) ||

  (arr[2][0] == ‘X’ && arr[2][1] == ‘X’ && arr[2][2] == ‘X’))

                                 cout<<”Player X has won by getting three X’s in a column”;

C)

if((arr[0][0] == ‘X’ || arr[1][0] == ‘X’ || arr[2][0] == ‘X’) &&

   (arr[0][1] == ‘X’ || arr[1][1] == ‘X’ || arr[2][1] == ‘X’) &&

  (arr[0][2] == ‘X’ || arr[1][2] == ‘X’ || arr[2][2] == ‘X’))

                                 cout<<”Player X has won by getting three X’s in a column”;

D)

if((arr[0][0] == ‘X’ && arr[1][0] == ‘X’ && arr[2][0] == ‘X’) ||

   (arr[0][1] == ‘X’ && arr[1][1] == ‘X’ && arr[2][1] == ‘X’) ||

(arr[0][2] == ‘X’ && arr[1][2] == ‘X’ && arr[2][2] == ‘X’))

                               cout<<”Player X has won by getting three X’s in a column”;

Question 3)

Suppose a program is supposed to search an array to see if a value occurs in the array. For example, if the array arr = [1, 2, 3, 4, 5, 6] and the search value search_value = 6, then the program would print out “Search value found”, because 6 occurs in the array. On the other hand, if the array arr = [1, 2, 3, 4, 5, 6], and the search value search_value = 7, the program would print out “Search value NOT found”, because 7 does NOT occur in the array.

NOTE: arr is an array storing numbers, SIZE is the size of the array, and search_value is the value that is being searched for in the array.

Which of the options below is the correct implementation of the program?

Group of answer choices

int i=0;

while(i < SIZE && arr[i] != search_value)

      i++;

if(i == SIZE)

       cout<<"Search value NOT found"<<endl;

else

    cout<<"Search value found"<<endl;

int i=0;

while(i < SIZE && arr[i] != search_value)

      i++;

if(i == SIZE)

       cout<<"Search value found"<<endl;

else

    cout<<"Search value NOT found"<<endl;

int i=0;

while(i < SIZE && arr[i] == search_value)

      i++;

if(i == SIZE)

       cout<<"Search value found"<<endl;

else

    cout<<"Search value NOT found"<<endl;

int i=0;

while(i < SIZE && arr[i] == search_value)

      i++;

if(i == SIZE)

       cout<<"Search value NOT found"<<endl;

else

    cout<<"Search value found"<<endl;

Question 4)

Suppose a program has the following 4X4 2D array with 16 (sixteen) cells:

1	2	3	4
5	6	7	8
9	10	11	12
13	14	15	16

The goal of the program is to print out the four bolded diagonal values in the following order:

16, 11, 6, 1

Which of the options below is the correct implementation?

Group of answer choices

A-)

for(int curr_row=0, curr_col=0; curr_row<ROWS && curr_col<COLS;

curr_row++, curr_col++)

             cout<<arr[curr_row][curr_col]<<endl;

C-)

for(int curr_row=0, curr_col=COLS-1; curr_row<ROWS && curr_col>=0;

curr_row++, curr_col--)

             cout<<arr[curr_row][curr_col]<<endl;

D-)

for(int curr_row=ROWS-1, curr_col=0; curr_row>=0 && curr_col<COLS;

curr_row--, curr_col++)

             cout<<arr[curr_row][curr_col]<<endl;

B-)

for(int curr_row=ROWS-1, curr_col=COLS-1; curr_row>=0 && curr_col>=0;

curr_row--, curr_col--)

             cout<<arr[curr_row][curr_col]<<endl;

Question 5)

NOTE: ARR_SIZE is the size of the array letters, NUM_OF_FILE_LINES is the number of lines in the file that is associated with the file object inputfile, and count is initialized to zero (0).

Assume that NUM_OF_FILE_LINES is greater than or equal to ARRAY_SIZE. If NUM_OF_FILE_LINES is greater than ARRAY_SIZE, then only the first ARRAY_SIZE lines from the file will be read into the array.

All of the options below will correctly read the contents of a file into an array EXCEPT:

Group of answer choices

while(count < ARR_SIZE && inputfile >> letters[count])

          count++;

while(inputfile >> letters[count] && count < ARR_SIZE)

          count++;

for(int i=0; i<NUM_OF_FILE_LINES; i++)

      {                      

        if(i < ARR_SIZE)

               inputfile >> letters[i];

        else

             break;

      }

for(int i=0; i<ARR_SIZE; i++)

                              inputfile >> letters[i];

Answer 1

Please find your answers below and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. If not, PLEASE let me know before you rate, I’ll help you fix whatever issues. Thanks

Question 1)

Suppose a program has the following code:

const int X = 2, Y = 3;

int sum;

int values[X][Y] = {{1, 2, 3},

                                 {4, 5, 6}};

for(int i=0; i<X; i++)

{

     sum=0;

     for(int j=0; j<Y; j++)

        sum+=values[i][j];

   cout<<sum<<endl;

}

What is this program getting the sum of?

Answer: D-) The columns of the 2D array.

Explanation: The program loops through each row, initializes sum to 0, and then loop through each column in current row, adding each element to sum, and finally displays the sum after the inner loop terminates. And then moves on to the next row.

Question 2)

In the game of tic-tac-toe, two players (‘X’ and ‘O’) play against each other on a 3X3 (three by three) grid with 9 (nine) squares. There are three ways to win the game:

Get three of your symbol (‘X’ or ‘O’) in a row

Get three of your symbol (‘X’ or ‘O’) in a column

Get three of your symbol (‘X’ or ‘O’) diagonally

Which of the options below correctly determines if player X has won the game by getting three X’s in a column?

Answer: option B.

if((arr[0][0] == ‘X’ && arr[0][1] == ‘X’ && arr[0][2] == ‘X’) ||

   (arr[1][0] == ‘X’ && arr[1][1] == ‘X’ && arr[1][2] == ‘X’) ||

(arr[2][0] == ‘X’ && arr[2][1] == ‘X’ && arr[2][2] == ‘X’))

                                 cout<<”Player X has won by getting three X’s in a column”;

Explanation: This if statement checks if the columns at first row is all X’ or if the columns at second row is all X’ or if the columns at third row is all X’. If either one is true, “Player X has won by getting three X’s in a column” is printed.

Question 3)

Suppose a program is supposed to search an array to see if a value occurs in the array. For example, if the array arr = [1, 2, 3, 4, 5, 6] and the search value search_value = 6, then the program would print out “Search value found”, because 6 occurs in the array. On the other hand, if the array arr = [1, 2, 3, 4, 5, 6], and the search value search_value = 7, the program would print out “Search value NOT found”, because 7 does NOT occur in the array.

NOTE: arr is an array storing numbers, SIZE is the size of the array, and search_value is the value that is being searched for in the array.

Which of the options below is the correct implementation of the program?

Answer: Option numbers/labels are not visible, so I’m just writing down the code of correct answer:

int i=0;

while(i < SIZE && arr[i] != search_value)

      i++;

if(i == SIZE)

       cout<<"Search value NOT found"<<endl;

else

    cout<<"Search value found"<<endl;

Explanation: The code first initializes i to 0. Then it loops as long as i is a valid index (0 to SIZE-1) and element at i is not search_value. In every loop, the value of i is incremented. So after the loop, if i is SIZE, then we have not found search value in the array, otherwise, we found the search value at index i.

Question 4)

Suppose a program has the following 4X4 2D array with 16 (sixteen) cells:

The goal of the program is to print out the four bolded diagonal values in the following order:

16, 11, 6, 1

Which of the options below is the correct implementation?

Answer: option B-)

for(int curr_row=ROWS-1, curr_col=COLS-1; curr_row>=0 && curr_col>=0;

curr_row--, curr_col--)

             cout<<arr[curr_row][curr_col]<<endl;

Explanation: this option will start at last row and last column, prints the value, then moves to second last row, second last column, prints the next value and continue this upto first row, first column.

Question 5)

NOTE: ARR_SIZE is the size of the array letters, NUM_OF_FILE_LINES is the number of lines in the file that is associated with the file object inputfile, and count is initialized to zero (0).

Assume that NUM_OF_FILE_LINES is greater than or equal to ARRAY_SIZE. If NUM_OF_FILE_LINES is greater than ARRAY_SIZE, then only the first ARRAY_SIZE lines from the file will be read into the array.

All of the options below will correctly read the contents of a file into an array EXCEPT:

Answer: Since option numbers are not visible, I’m just writing down the code of correct answer (wrong option):

while(inputfile >> letters[count] && count < ARR_SIZE)

          count++;

Explanation: Out of all options given, this must be the wrong one. This is because, imagine if count currently equals ARR_SIZE. i.e the array is full, then when the while loop executes the condition at hand side of the && operator, which is inputfile >> letters[count], will cause error as count is not a valid index of letters array. So count < ARR_SIZE must be on the left side of && operator.