charpter5

Question 1

5.1 What will the following program segments display?
A) x = 2;
y = x++;
cout

Answer 1

A) 32
B) 33
C) 23
D) 34
E) It is true!
F) It is true!

Question 2

5.2 Write an input validation loop that asks the user to enter a number in the range of
10 through 25.

Answer 2

int number;
cout &laquo_space;“Enter a number in the range 10 through 25: “;
cin&raquo_space; number;
while (number < 10 || number > 25)
{
cout &laquo_space;“Error! The number must be in the range “
&laquo_space;“of 10 through 25. Enter a valid number: “;
cin&raquo_space; number;
}

Question 3

5.3 Write an input validation loop that asks the user to enter Y , y , N , or n .

Answer 3

char letter;
cout << "Enter Y for yes or N for no: ";
cin >> letter;
while (letter != 'Y' && letter != 'y' &&
letter != 'N' && letter != 'n')
{
cout << "Error! Enter either Y or N: ";
cin >> letter;
}

Question 4

5.4 Write an input validation loop that asks the user to enter Yes or No .

Answer 4

string input;
cout << "Enter Yes or No: ";
cin >> input;
while ( (input != "Yes") && (input != "No") )
{
cout << "Error! Enter either Yes or No: ";
cin >> input;
}

Question 5

5.5 What will the following program segments display?
A) int count = 10;
do
{
cout

Answer 5

A) Hello World
B) 10
C) 8 4

Question 6

5.6 Name the three expressions that appear inside the parentheses in the for loop s
header.

Answer 6

Initialization, test, and update.

Question 7

You want to write a for loop that displays I love to program 50 times. Assume
that you will use a counter variable named count.
A) What initialization expression will you use?
B) What test expression will you use?
C) What update expression will you use?
D) Write the loop.

Answer 7

A) int count = 1;

B) count

Question 8

5.8 What will the following program segments display?

A) for (int count = 0; count

Answer 8

A) 0246810
B) -5-4-3-2-101234
C) 5
8
11
14
17

Question 9

5.9 Write a for loop that displays your name 10 times.

Answer 9

for (int count = 1; count &laquo_space;“Chris Coder\n”;

Question 10

5.10 Write a for loop that displays all of the odd numbers, 1 through 49.

Answer 10

for (int count = 1; count &laquo_space;count &laquo_space;endl;

Question 11

5.11 Write a for loop that displays every fth number, zero through 100.

Answer 11

for (int count = 0; count &laquo_space;count &laquo_space;endl;

Question 12

5.12 Write a for loop that repeats seven times, asking the user to enter a number. The
loop should also calculate the sum of the numbers entered.

Answer 12

int number, total = 0;
for (int count = 0; count < 7; count++)
{
cout << "Enter a number: ";
cin >> number;
total += number;
}

Question 13

5.13 In the following program segment, which variable is the counter variable and
which is the accumulator?
int a, x, y = 0;
for (x = 0; x > a;
y += a;
}
cout

Answer 13

5.13 The variable x is the counter variable. The variable y is the accumulator

Question 14

5.14 Why should you be careful when choosing a sentinel value?

Answer 14

You must be sure to choose a sentinel value that could not be mistaken as a member of the
data list.

Question 15

5.15 How would you modify Program 5-13 so any negative value is a sentinel?

Answer 15

5.15 Change the while loop to read:

while (points >= 0)

Question 16

5.16 What is an output le? What is an input le?

Answer 16

An output file is a file that data is written to. An input file is a file that data is read from.

Question 17

5.17 What three steps must be taken when a le is used by a program?

Answer 17

1. Open the file
2. Process the file
3. Close the file

Question 18

5.18 What is the difference between a text le and a binary le?

Answer 18

A text file contains data that has been encoded as text, using a scheme such ASCII or
Unicode. Even if the file contains numbers, those numbers are stored in the file as a
series of characters. As a result, the file may be opened and viewed in a text editor
such as Notepad. A binary file contains data that has not been converted to text. As a
consequence, you cannot view the contents of a binary file with a text editor.

Question 19

5.19 What is the difference between sequential access and random access?

Answer 19

When you work with a sequential access file, you access data from the beginning of the file
to the end of the file. When you work with a random access file, you can jump directly to
any piece of data in the file without reading the data that comes before it.

Question 20

5.20 What type of le stream object do you create if you want to write data to a le?

Answer 20

ofstream

Question 21

5.21 What type of le stream object do you create if you want to read data from a le?

Answer 21

ifstream

Question 22

5.22 Write a short program that uses a for loop to write the numbers 1 through 10 to
a le.

Answer 22

ofstream outputFile("num.txt");
for (int num = 1; num << num << endl;
outputFile.close();

Question 23

5.23 Write a short program that opens the le created by the program you wrote for
Checkpoint 5.22, reads all of the numbers from the le, and displays them.

Answer 23

ifstream inputFile("num.txt");
int num;
while (inputFile >> num)
cout << num << endl;
inputFile.close();

Question 24

5.24 The following code has an error. Can you correct it?
// Find the error and correct it.
ofstream outputFile;
string filename = "Test.txt";
outputFile.open(filename);

Answer 24

ofstream outputFile;
string filename = “Test.txt”;
outputFile.open(filename.c_str());