COMSC Chapter 5 Practice

What will the following loop display? int x = 0; while (x < 5) { cout << x << endl; x++; } ● 0 1 2 3 4 5 ● 0 1 2 3 4 ● 0 1 2 3 4 ● The loop will display numbers starting at 0, for infinity.

0 1 2 3 4

What is the output of the following code segment? n = 1; for ( ; n <= 5; ) cout << n << ' '; n++; 2 3 4 5 6 1 1 1 ... and on forever 1 2 3 4 5 2 3 4 5 1 2 3 4

1 1 1 ... and on forever

What is the output of the following code segment? n = 1; while (n <= 5) cout << n << ' '; n++; 2 3 4 5 6 1 2 3 4 5 1 2 3 4 1 1 1... and on forever 2 3 4 5

1 1 1... and on forever

How many times will the following loop display "Hello"? for (int i = 1; i < 20; i++) cout << "Hello!" << endl; 20 19 21 An infinite number of times

19

How many times will the following loop display "Hello"? for (int i = 20; i > 0; i--) cout << "Hello!" << endl; 20 19 21 An infinite number of times

20

How many times will the following loop display "Hello"? for (int i = 0; i <= 20; i++) cout << "Hello!" << endl; 20 19 21 An infinite number of times

21

What will the following code display? int number = 6; cout << ++number << endl; 6 5 7 0

7

In a for statement, this expression is executed only once. test ●initialization ●null ●validation ●None of these

initialization

The while loop contains an expression that is tested for a true or false value, and a statement or block that is repeated as long as the expression: does not evaluate to true or false evaluates to true or false is true is false None of these

is true

The while loop is this type of loop. infinite post-test limited pre-test None of these

pre-test

What will the following code display? int x = 0; for (int count = 0; count < 3; count++) x += count; cout << x << endl; ●6 ●3 ●0 ●0 1 2

3

What will the following code display? int number = 6 int x = 0; x = --number; cout << x << endl; 6 5 7 0

5

What will the following code display? int number = 6; int x = 0; x = number--; cout << x << endl; 6 5 7 0

6

What will the following code display? int number = 6; cout << number++ << endl; 6 5 7 0

6

What will the following code display? int number = 6; ++number; cout << number << endl; 6 5 7 0

7

What will the following code display? int number = 6; number++; cout << number << endl; 6 5 7 0

7

Look at the following statement. while (x++ < 10) Which operator is evaluated first? < ++ Neither. The expression is invalid.

<

The while loop has two important parts: an expression that is tested for a true or false value, and: A) a statement or block that is repeated as long as the expression is true B) a statement or block that is repeated once, if the expression is true C) a statement or block that is repeated only if the expression is false D) one line of code that is repeated once, if the expression is true

A) a statement or block that is repeated as long as the expression is true

True/False: A while loop is somewhat limited, because the counter can only be incremented by one each time through the loop.

False

True/False: The increment and decrement operators can be used in mathematical expressions; however, they cannot be used in relational expressions.

False

True/False: The scope of a variable declared in a for loop's initialization expression always extends beyond the body of the loop.

False

True/False: You may nest while and do-while loops, but you may not nest for loops.

False

True/False: You may not use the break and continue statements within the same set of nested loops.

False

True/False: You may not use the break statement in a nested loop.

False

True/False: A while loop's body can contain multiple statements, as long as they are enclosed in braces.

True

True/False: An initialization expression may be omitted from the for loop if no initialization is required.

True

True/False: An output file is a file that data is written to.

True

True/False: If you want to stop a loop before it goes through all its iterations, the break statement may be used.

True

True/False: In C++ 11 you can pass a string object as argument to a file stream object's open member function.

True

True/False: It is possible to define a file stream object and open a file in one statement.

True

True/False: Multiple relational expressions cannot be placed into the test condition of a for loop.

True

True/False: The update expression of a for loop can contain more than one statement, e.g. counter++, total+= sales.

True

True/False: string objects have a member function named c_str that returns the contents of the object formatted as a null-terminated C-string.

True

A loop that is inside another loop is called: a pre-test loop a nested loop a post-test loop an infinite loop None of these

a nested loop

The statements in the body of a while loop may never be executed, whereas the statements in the body of a do-while loop will be executed: at least twice never at least once as many times as the user wishes None of these

at least once

This statement causes a loop to terminate early. ●terminate ●break ●null ●stop ●None of these

break

This statement may be used to stop a loop's current iteration and begin the next one. re-iterate break terminate continue None of these

continue

This is a variable that is regularly incremented or decremented each time a loop iterates. counter null terminator constant control statement None of these

counter

If you want a user to enter exactly 20 values, which loop would be the best to use? for do-while infinite while None of these

for

This loop is a good choice when you know how many times you want the loop to iterate in advance of entering the loop. ●while ●do-while ●for ●infinite ●None of these

for

This means to increase a value by one. decrement parse increment modulus None of these

increment

Something within a while loop must eventually cause the condition to become false, or a(n) ________ results. infinite loop compiler error null value unexpected exit None of these

infinite loop

This is a control structure that causes a statement or group of statements to repeat. constant cout object decision statement loop None of these

loop

If you place a semicolon after the test expression in a while loop, it is assumed to be a(n): post-test loop null statement pre-test loop infinite loop None of these

null statement

The do-while loop is considered a(n) ________ loop. pre-test limited infinite post-test None of these

post-test

When the increment operator precedes its operand, as in ++num1, the expression is in this mode. binary preliminary prefix postfix None of these

prefix

This operator increments the value of its operand, then uses the value in context. prefix decrement prefix increment postfix decrement postfix increment None of these

prefix increment

This is a special value that marks the end of a list of values. variable loop constant sentinel None of these

sentinel

A for statement contains three expressions: initialization, test, and reversal null update validation None of these

update

You may define a ________ in the initialization expression of a for loop. new data type function constant variable None of these

variable

This is a pre-test loop that is ideal in situations where you do not want the loop to iterate if the condition is false from the beginning. do-while while for infinite None of these

while