Module 03 Making Decisions

This operator performs a logical NOT operation.

!

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

!

This operator represents the logical AND.

&&

What is assigned to the variable a given the statement below with the following assumptions: x = 10, y = 7, and z, a, and b are all int variables. a = x >= y;

1

Assuming x is 5, y is 6, and z is 8, which of the following (2) are false? 1. x == 5; 2. 7 <= (x + 2); 3. z < = 4; 4. (1 + x) != y; 5. z >= 8; 6. x >= 0; 7. x <= (y * 2)

3 and 4 are false.

This operator is used in C++ to represent equality.

==

What will be the value of result after the following code has been executed? int a = 60; int b = 15; int result = 10; if (a = b) result *= 2; A) 10 B) 120 C) 20 D) This code will not compile.

C

Which of the following expressions will determine whether x is less than or equal to y? A) x > y B) x =< y C) x <= y D) x >= y

C

What is the value of donuts after the following code executes? int donuts = 10; if (donuts = 1) donuts = 0; else donuts += 2; A) 12 B) 10 C) 0 D) 1

C (0)

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"; A) 100 B) 10 C) 99 D) 0 E) All of these

C (99)

What will the following segment of code output if the value 11 is entered at the keyboard? int number; cin >> number; if (number > 0) cout << "C++"; else cout << "Soccer"; cout << " is "; cout << "fun" << endl;

C++ is fun

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

Relational expression

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 << "This is all folks!" << endl;

This is true! This is all folks!

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

break

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" and then advance to a new line? A) if code is equal to C cout << "This is a check\n"; B) if (code = "C") cout << "This is a check" << endl; C) if (code == 'C') cout << "This is a check\n"; D) if (code == C) cout << "This is a check" << endl;

c

Relational operators allow you to ________ numbers.

compare

What is the value of the following expression? true && false

false

What will be the output of the following code segment after the user enters 0 at the keyboard? int x = -1; cout << "Enter a 0 or a 1 from the keyboard: "; cin >> x; if (x) cout << "true" << endl; else cout << "false" << endl;

false

This is a variable, usually a bool or an int, that signals when a condition exists.

flag

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

input validation

The ________ of a variable is limited to the block in which it is declared.

scope

What will the following program display? #include <iostream> using namespace std; int main() { int a = 0, b = 2, x = 4, y = 0; cout << (a == b) << " "; cout << (a != b) << " "; cout << (b <=x) << " "; cout << (y > a) << endl; return 0; } A) 0 1 1 0 B) 0 0 1 0 C) 1 1 0 1 D) 1 0 0 1 E) None of these

A (0 1 1 0)

What is the value of donuts after the following code executes? int donuts = 10; if (donuts != 10) donuts = 0; else donuts += 2; A) 12 B) 10 C) 0 D) 2

A (12)

Which line in the following program will cause a compiler error? 1 #include <iostream> 2 using namespace std; 3 4 int main() 5 { 6 int number = 5; 7 8 if (number >= 0 && <= 100) 9 cout << "passed.\n"; 10 else 11 cout << "failed.\n"; 12 return 0; 13 } A) 6 B) 8 C) 10 D) 9

B (8)

Given that, x = 2, y = 1, and z = 0, what will the following cout statement display? cout << "answer = " << (x || !y && z) << endl; A) answer = 0 B) answer = 1 C) answer = 2 D) None of these

B (answer = 1)

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

Curly braces { }

What will the following program segment display? 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; A) 7 15 B) 0 0 C) 10 10 D) 1 1 E) None of these

D (1 1)

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; } A) 98 B) 99 C) 0 D) 1

D (1)

What will the following segment of code output? Assume the user enters a grade of 90 from the keyboard. cout << "Enter a test score: "; cin >> test_score; if (test_score < 60); cout << "You failed the test!" << endl; if (test_score > 60) cout << "You passed the test!" << endl; else cout << "You need to study for the next test!";

You failed the test! You passed the test!

In C++ the = operator indicates:

assignment

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

logical

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

nesting

What is the value of the following expression? false || true

true

What is the value of the following expression? true && true

true

What is the value of the following expression? true || true

true

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

zero

This operator is known as the logical OR operator.

||

After execution of the following code, what will be the value of input_value if the value 0 is entered at the keyboard at run time? cin >> input_value; if (input_value > 5) input_value = input_value + 5; else if (input_value > 2) input_value = input_value + 10; else input_value = input_value + 15;

15

True/False: The default section is required in a switch statement.

FALSE

True/False: An expression that has any value other than 0 is considered true by an if statement.

TRUE

If you place a semicolon after the statement: if (x < y)

The compiler will interpret the semicolon as a null statement.

The default section of a switch statement performs a similar task as the ________ portion of an if/else if statement.

trailing else

What is the output of the following segment of code if the value 4 is input by the user when asked to enter a number? 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;

13

Given the following code segment, what is output after "result = "? int x = 1, y = 1, z = 1; y = y + z; x = x + y; cout << "result = " << (x < y ? y : x) << endl; A) 0 B) 1 C) 2 D) 3 E) None of these

D (3)

Input values should always be checked for: A) Appropriate range B) Reasonableness C) Division by zero, if division is taking place D) All of these E) None of these

D (All of these)

True/False: The following code correctly determines whether x contains a value in the range of 0 through 100. if (x >= 0 && <= 100)

FALSE

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

TRUE

True/False: Both of the following if statements perform the same operation. if (sales > 10000) commissionRate = 0.15; if (sales > 10000) commissionRate = 0.15;

TRUE

True/False: If the sub-expression on the left side of an && operator is false, the expression on the right side will not be checked.

TRUE

True/False: If the sub-expression on the left side of the || operator is true, the expression on the right side will not be checked.

TRUE

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

TRUE

What will the following segment of code output? score = 40; if (score > 95) cout << "Congratulations!\n"; cout << "That's a high score!\n"; cout << "This is a test question!" << endl;

That's a high score! This is a test question!

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

switch