6.7. Multiple Choice Exercises

Answer the following Multiple Choice questions to assess what you have learned in this chapter.

Q2

What is printed when the following code executes?

int x = 8;

if (x % 3 == 2) {
    cout << "hey!" << '\n';
} else if (x != 7) {
    cout << "hi!" << '\n';
} else if (x % 2 == 0) {
    cout << "hello!" << '\n';
} else {
    cout << "bye!" << '\n';
}

:: none

hey!

• Since the first conditon is met, the rest of the chained conditional does not execute.

:: none

hi!

• It's true that 8 != 7, but "hi!" is not printed here.

:: none

hi!

• It's true that 8 % 2 == 0, but "hello!" is not printed!

:: none

hey! hi! hello!

• All of these conditons are met, but only one expression is printed!

:: none

bye!

• At least one of the conditons is met, so the else will not execute!

Check answer

Q3

What is printed when the following code executes?

int x = 34;

if (32 < x) {
    cout << "It's Freezing!";
}
if (x < 40) {
    cout << "It's Cold!";
}
if (x > 65) {
    cout << "It's Warm!";
} else {
    cout << "It's Hot!";
}

:: none

It's Freezing!

• Take a closer look at the conditions and the way they are written in the program.

:: none

It's Cold!

• Take a closer look at the conditions and the way they are written in the program.

:: none

It's Freezing! It's Cold!

• You've identified some of the conditons that are met! Take another look at the chain of conditionals at the end!

:: none

It's Freezing! It's Cold! It's Hot!

• These statements are quite contradicting, but that's exactly what the output would be if we ran this code.

:: none

It's Hot!

• Take a closer look at the conditions and the way they are written in the program.

Check answer

Q4

Suppose you have defined the following function:

void practicing_returns (int a, int b) {
    if (a < b) {
        a += 2;
    }
    if (a > b) {
        return;
    }
    cout << a + b;
}

What is printed when we run the following code?

int x = practicing_returns(2, 3);

5

• This is what a + b would be before the first conditonal.

7

• This is the value of a + b after the first conditional, but it doesn't print.

23

• This is not the value of a + b.

Nothing.

• The function exits with a return before anything is printed.

Check answer

Q5

Suppose you have defined the following function:

void fortune_cookie (int a, bool b, char c) {
    if (c < 'm') {
        if (a % 2 == 0) {
            cout << "An alien of some sort will be appearing to you shortly.";
        } else {
            cout << "The fortune you seek is in another cookie.";
        }
    } else if (c < 'r') {
        if (b) {
            cout << "He who laughs at himself never runs out of things to laugh at.";
        } else {
            cout << "You will be hungry again in one hour.";
        }
    } else {
        cout << "Fortune not found? Abort, retry, ignore.";
    }
}

What will be your fortune if you run the following code?

fortune_cookie(14, false, 'm');

An alien of some sort will be appearing to you shortly.

• 'm' is NOT less than 'm', so you don't even enter the if block.

The fortune you seek is in another cookie.

• 'm' is NOT less than 'm', so you don't even enter the if block.

He who laughs at himself never runs out of things to laugh at.

• if (b) really means if (b == true).

You will be hungry again in one hour.

• 'm' < 'r' is true and b == false, so this is the fortune that will print.

Fortune not found? Abort, retry, ignore.

• 'm' is less than 'r' so you would enter the else if block, not the else.

Check answer

Q6

Suppose you have defined the following function:

void fortune_cookie (int a, bool b, char c) {
    if (c < 'm') {
        if (a % 2 == 0) {
            cout << "An alien of some sort will be appearing to you shortly.";
        } else {
            cout << "The fortune you seek is in another cookie.";
        }
    } else if (c < 'r') {
        if (b) {
            cout << "He who laughs at himself never runs out of things to laugh at.";
        } else {
            cout << "You will be hungry again in one hour.";
        }
    } else {
        cout << "Fortune not found? Abort, retry, ignore.";
    }
}

What will be your fortune if you run the following code?

fortune_cookie(22, true, 'b');

An alien of some sort will be appearing to you shortly.

• 'b' < 'm' and 22 % 2 == 0, so this is the fortune that will print.

The fortune you seek is in another cookie.

• 22 % 2 == 0, so you enter the if block, not the else.

He who laughs at himself never runs out of things to laugh at.

• 'b' is less than 'm', so you would enter the if block, not the else if.

You will be hungry again in one hour.

• 'b' is less than 'm', so you would enter the if block, not the else if.

Fortune not found? Abort, retry, ignore.

• 'b' is less than 'm', so you would enter the if block, not the else.

Check answer

Q7

Suppose you have defined the following function:

void the_thing (int m, int n, bool b) {
    if (b) {
        if (m % 4 == 0) {
            cout << m;
            return;
        }
        if ((m + n) > 10) {
            cout << m + n;
            return;
        }
    } else if ((m > n) == b) {
        cout << m - n;
        return;
    } else {
        if (n % 3 == 0) {
            cout << n;
            return;
        }
    }
    cout << -1;
}

What is printed when we run the following code?

the_thing (5, 10, false);

5

• The outer if condition is not met, the block does not execute.

15

• The outer if condition is not met, the block does not execute.

-5

• m > n evaluates to false, so the else if block executes.

10

• The condition for else if is met, so the function never enters the else.

-1

• The function has returned.

Check answer

Q8

Suppose you have defined the following function:

void the_thing (int m, int n, bool b) {
    if (b) {
        if (m % 4 == 0) {
            cout << m;
            return;
        }
        if ((m + n) > 10) {
            cout << m + n;
            return;
        }
    } else if ((m > n) == b) {
        cout << m - n;
        return;
    } else {
        if (n % 3 == 0) {
            cout << n;
            return;
        }
    }
    cout << -1;
}

What is printed when we run the following code?

the_thing (6, 4, true);

6

• 5 % 4 != 0 in the if block, so the function doesn't print 6.

10

• m + n !> 10 in the if block, so the function doesn't print 10.

2

• The condition for if is met, so the function never enters the else if.

4

• The condition for if is met, so the function never enters the else.

-1

• None of the conditions were met, so we reach the default cout -1.

Check answer

Q9

Suppose you have defined the following function:

void moo (int m, int n) {
    if (m != n) {
        m += 2;
        cout << "Moo!";
        moo (m, n);
    } else {
        cout << "Got Milk?";
    }
}

How many times does "Moo!" print when we run the following?

moo (4, 8);

0

• When we call the function 4 != 8, so "Moo!" is printed at least once.

1

• The function calls itself inside of the if loop, so "Moo!" is printed more than once.

2

• m is incremented by two each with each function call, so after two m == n and the recursion stops.

3

• Take a look at how m is incremented with each function call.

infinite recursion

• The function stops printing "Moo!" when m == n.

Check answer

Q10

Suppose you have defined the following function:

void moo (int m, int n) {
    if (m != n) {
        m += 2;
        cout << "Moo!";
        moo (m, n);
    } else {
        cout << "Got Milk?";
    }
}

How many times does "Moo!" print when we run the following?

moo (5, 10);

0

• When we call the function 5 != 10, so "Moo!" is printed at least once.

1

• The function calls itself inside of the if loop, so "Moo!" is printed more than once.

2

• After two function calls, m == 9 and n == 10. The function is not done printing.

3

• After three function calls, m == 11 and n == 10. The function is not done printing

infinite recursion

• The function stops printing "Moo!" when m == n, but since m is odd and n is even, they will never be equal as long as we increment by two.

Check answer