Exam Questions Ch4 Making Decisions

Starting Out with C++ from Control Structures to Objects, 9e (Gaddis)

Chapter 4 Making Decisions

TRUE/FALSE

1. If the expression on the left side of the following is true, the expression on the right side will not be checked.

(a > = b) || (c == d)

2. If the expression on the left side of the following is false, the expression on the right side will not be checked.

(a > = b) && (c == d)

3. The default section is required in a switch statement.

4. An expression that has any value other than 0 is considered true by an if statement.

5. Both of the following if statements perform the same operation.

1. if (sales > 10000)

commissionRate = 0.15;

2. if (sales > 10000) commissionRate = 0.15;

6. You should be careful when using the equality operator to compare floating point values because of potential round-off errors.

7. As a rule of style, when writing an if statement you should indent the conditionally-executed statements.

8. The following code correctly determines whether x contains a value in the range of 0 through 100, inclusive.

if (x > 0 && <= 100)

9. The value of result in the following expression will be 0 if x has the value of 12.

result = x > 100 ? 0 : 1;

10. The conditional operator takes two operands.

MULTIPLE CHOICE

1. Relational operators allow you to __________ numbers.

2. After the following code executes, what is the value of my_value if the user enters 0?

cin >> my_value;

if (my_value > 5)

my_value = my_value + 5;

else if (my_value > 2)

my_value = my_value + 10;

else

my_value = my_value + 15;

3. After the following code executes, what is the output if user enters 0?

int x = -1;

cout << "Enter a 0 or 1: ";

cin >> x;

if (c)

cout << "true" << endl;

else

cout << "false" << endl;

4. What is assigned to the variable result given the statement below with the following assumptions: x = 10, y = 7, and x, result, and y are all int variables.

result = x >= y;

5. If you place a semicolon after the statement:

if (x < y)

6. When a relational expression is false, it has the value

7. What is the output of the following code segment?

int x = 5;

if (x = 2)

cout << "This is true!" << endl;

else

cout << "This is false!" << endl;

cout << "That's all, folks!" << endl;

8. What is the output of the following code segment if the user enters 90 for the score?

cout << "Enter your test score: ";

cin >> test_score;

if (test_score < 60)

cout << "You failed the test." << endl;

if (test_score > 60)

cout << "You passed the test."

else

cout << "You need to study harder next time." << endl;

9. Whereas < is called a relational operator, x < y is called a(n)

10. The __________ is an equality (or comparison) operator.

11. What is the output of the following code segment if the user enters 23?

int number;

cout << "Enter a number: ";

cin >> number;

if (number > 0)

cout << "Hi, there!" << endl;

else

cout << "Good-bye." << endl;

12. What will be displayed after the following statements execute?

int funny = 7, serious = 15;

funny = serious % 2;

if (funny != 1)

{

funny = 0;

serious = 0;

}

else if (funny == 2)

{

funny = 10;

serious = 10;

}

else

{

funny = 1;

serious = 1;

}

cout << funny << " " << serious << endl;

13. What is the value of donuts after the following statement executes?

int donuts = 10;

if (donuts != 10)

donuts = 0;

else

donuts += 2;

14. What is the value of donuts after the following statement executes?

int donuts = 10;

if (donuts = 1)

donuts = 0;

else

donuts += 2;

15. Which of the following expressions will determine whether x is less than or equal to y?

16. What is the value of result after the following code executes?

int a = 60;

int b = 15;

int result = 10;

if (a = b)

result *= 2;

17. When an if statement is placed within the conditionally-executed code of another if statement, this is known as

18. If you intend to place a block of statements within an if statement, you must place __________ around the block:

19. A variable, usually a bool or an int, that signals when a condition exists is known as a(n)

20. This operator represents the logical AND:

21. This operator represents the logical OR:

22. This operator takes an operand and reverses its truth or falsehood:

23. What is the value of the following expression?

true && false

24. What is the value of the following expression?

true && true

25. What is the value of the following expression?

true || false

26. What is the value of the following expression?

true && !false

27. These operators connect two or more relational expressions into one, or reverse the logic of an expression.

28. Which value can be entered to cause the following code segment to display the message "That number is acceptable"?

int number;

cin >> number;

if (number > 10 && number < 100)

cout << "That number is acceptable.\n";

else

cout << "That number is not acceptable.\n";

29. Which of the following is evaluated first, given the expression:

A && B || C && !D

30. What is the output of the following code?

int w = 98;

int x = 99;

int y = 0;

int z = 1;

if (x >= 99)

{

if (x < 99)

cout << y << endl;

else

cout << z << endl;

}

else

{

if (x == 99)

cout << x << endl;

else

cout << w << endl;

}

31. Which line in the following program will cause a compiler error?

1 #include <iostream>

2 using namespace std;

3 int main()

4 {

5 int number = 5;

6 if (number >= 0 && <= 100)

7 cout << "passed.\n";

8 else

9 cout << "failed.\n";

10 return 0;

11 }

32. Given that x = 2, y = 1, z = 0, what will the following cout statement display?

cout << "answer = " << (x || !y && z) << endl;

33. What is the output of the following segment of code if the value 4 is input by the user?

int num;

int total = 0;

cout << "Enter a number from 1 to 10: ";

cin >> num;

switch (num)

{

case 1:

case 2: total = 5;

case 3: total = 10;

case 4: total = total + 3;

case 8: total = total + 6;

default: total = total + 4;

}

cout << total << endl;

34. This statement uses the value of a variable or expression to determine where the program will branch to.

35. Without this statement appearing in a switch construct, the program "falls through" all of the statements below the one with the matching case expression.

36. The default section of a switch statement performs a similar task similar to the __________ portion of an if/else if statement.

37. Which statement allows you to properly check the char variable code to determine whether it is equal to a C and then output This is a check?

38. Given the following code segment, what is the output?

int x = 1, y = 1, z = 1;

y = y + z;

x = x + y;

cout << "result = " << (x < y ? y : x) << endl;

39. Given the if/else statement:

if (a < 5)

b = 12;

else

d = 30;

Which of the following performs the same operation?

40. When a program lets the user know that an invalid choice has been made, this is known as:

41. Input values should always be checked for

MULTIPLE RESPONSE

1. Select all that apply. Given: x = 5, y = 6, z = 8. Which of the following are false?

1. x == 5;

2. x < (y + 2);

3. z <= 4;

4. y > (z - x);

5. z >= (y + x)

6. y <= 6