Programming 1: Chapter 5
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 only if the expression is false C) one line of code that is repeated once, if the expression is true D) a statement or block that is repeated once, if the expression is true
A
True/False: You may nest while and do-while loops, but you may not nest for loops.
FALSE
In a for statement, this expression is executed only once.
initialization
This is a control structure that causes a statement or group of statements to repeat. A) decision statement B) constant C) loop D) cout object E) None of these
C
This loop is a good choice when you know how many times you want the loop to iterate in advance of entering the loop. A) do-while B) while C) for D) infinite E) None of these
C
To allow file access in a program, you must #include this header file. A) file B) fileaccess C) fstream D) cfile
C
What will the following loop display? int x = 0; while (x < 5) { cout << x << endl; x++; }
0
How many lines will the following while loop display? int count = 1; while (count < 5) count << " My favorite day is Sunday \n"; count = count + 1;
0 lines - more than one statement, no curly braces. This means the line that increments count is not in the loop, so count always remains less than 5, causing an infinite loop. The cout statement executes over and over again until the user stops the program.
A for statement contains three expressions: initialization, test, and A) update B) reversal C) null D) validation E) None of these
A
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
What will the following program segments display? x = 2; y = ++x; cout << x << y;
3 3
What will the following program segments display? x = 2; y = 2 * x++; cout << x << y;
3 4
How many lines will the following while loop display? int count = 1; while (count < 5) { count << "My favorite day is Sunday \n"; count = count + 1; }
4 lines
How many times will the following loop display "Hello"? for (int i = 1; i < 20; i++) cout << "Hello!" << endl; A) 20 B) 19 C) 21 D) An infinite number of times
B
If you want a user to enter exactly 20 values, which loop would be the best to use? A) do-while B) for C) while D) infinite E) None of these
B
When the increment operator precedes its operand, as in ++num1, the expression is in this mode. A) postfix B) prefix C) preliminary D) binary E) None of these
B
True/False: Multiple relational expressions cannot be placed into the test condition of a for loop.
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
When used as part of an expression and/or in an assignment operation this operator increments the value of its operand before the operand is used in the expression, or assignment operation. prefix increment postfix increment prefix decrement postfix decrement
prefix increment
The do-while loop is considered a(n) ________ loop. A) pre-test B) post-test C) infinite D) limited E) None of these
B
To read data from a file, you define an object of this data type. A) inputFile B) ifstream C) fstream D) ofstream
B
What will the following loop display? int x = 0; while (x < 5) { cout << x << endl; x++; } A) 0 1 2 3 4 5 B) 0 1 2 3 4 C) 01 2 3 4 D) The loop will display numbers starting at 0, for infinity.
B
What will display when the following lines of code are executed? int count = 1 while (count < 10) { cout << count << " "; count = count + 2; }
1 3 5 7 9
This means to increase a value by one. A) decrement B) increment C) modulus D) parse E) None of these
B
How many times will the following loop display "Hello"? for (int i = 0; i <= 20; i++) cout << "Hello!" << endl; A) 20 B) 19 C) 21 D) An infinite number of times
C
You may define a ________ in the initialization expression of a for loop. A) constant B) function C) variable D) new data type E) None of these
C
True/False: The scope of a variable declared in a for loop's initialization expression always extends beyond the body of the loop.
FALSE
Something within a while loop must eventually cause the condition to become false, or a(n) ________ results. A) null value B) infinite loop C) unexpected exit D) compiler error E) None of these
B
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: A) is false B) is true C) does not evaluate to true or false D) evaluates to true or false E) None of these
B
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. A) do-while B) while C) for D) infinite E) None of these
B
This statement causes a loop to terminate early. A) stop B) break C) null D) terminate E) None of these
B
True/False: An output file is a file that data is written to.
TRUE
How many lines will the following while loop display? int count = 1; while (count < 5); { cout << "My favorite days is Sunday \n"; count = count + 1;
0 lines - semicolon after test expression. This causes an infinite loop that prints nothing.
Assuming dataFile is a file stream object, the statement: dataFile.close(); A) is illegal in C++ B) needs a filename argument to execute correctly C) closes a file D) is legal but risks losing valuable data E) None of these
C
Assuming outFile is a file stream object and number is a variable, which statement writes the contents of number to the file associated with outFile? A) write(outFile, number); B) outFile >> number; C) outFile << number; D) number >> outFile;
C
These are operators that add and subtract one from their operands. A) plus and minus B) ++ and -- C) binary and unary D) conditional and relational E) None of these
B
This is a variable that is regularly incremented or decremented each time a loop iterates. A) constant B) counter C) control statement D) null terminator E) None of these
B
A file ________ is a small holding section of memory that file-bound information is first written to. A) name B) number C) buffer D) segment E) None of these
C
How many lines will the following while loop display? int count = 10 while (count < 5) { cout << "My favorite day is Sunday \n"; count = count + 1 }
0 lines - the test condition of the line is initially false, so the body of the loop is never executed.
What will the following program segment display? x = 2; y = x++; cout << x << " " << y;
2
What will the following program segments display? x = 2; y = 4; cout << x++ << --y;
2 3
What will the following code display? int x = 0; for (int count = 0; count < 3; count++) x += count; cout << x << endl;
3
What will the following program segments display? x = 2; y = x++; cout << x << y;
3 2
How many times will the following loop display "Hello"? for (int i = 0; i < 20; i++) cout << "Hello!" << endl; A) 20 B) 19 C) 21 D) An infinite number of times
A
How many times will the following loop display "Hello"? for (int i = 20; i > 0; i--) cout << "Hello!" << endl; A) 20 B) 19 C) 21 D) An infinite number of times
A
The do-while loop is a(n) ________ loop that is ideal in situations where you always want the loop to iterate at least once. A) post-test B) pre-test C) infinite D) null-terminated E) None of these
A
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: A) at least once B) at least twice C) as many times as the user wishes D) never E) None of these
A
This operator increments the value of its operand, then uses the value in context. A) prefix increment B) postfix increment C) prefix decrement D) postfix decrement E) None of these
A
What will the following code display? int number = 6; int x = 0; x = number--; cout << x << endl; A) 6 B) 5 C) 7 D) 0
A
The while loop is this type of loop. A) post-test B) pre-test C) infinite D) limited E) None of these
B
A file must be ________ before data can be written to or read from it. A) closed B) opened C) buffered D) initialized E) None of these
B
Look at the following statement. while (x++ < 10) Which operator is used first? A) ++ B) < C) Neither. The expression is invalid.
B
What is the output of the following code segment? n = 1; while (n <= 5) cout << n << ' '; n++; A) 1 2 3 4 5 B) 1 1 1... and on forever C) 2 3 4 5 6 D) 1 2 3 4 E) 2 3 4 5
B
What will the following code display? int number = 6 int x = 0; x = --number; cout << x << endl; A) 6 B) 5 C) 7 D) 0
B
A loop that is inside another loop is called: A) an infinite loop B) a pre-test loop C) a post-test loop D) a nested loop E) None of these
D
This is a special value that marks the end of a list of values. A) constant B) variable C) loop D) sentinel E) None of these
D
This may be used to write information to a file. A) cout object B) pen object C) output object D) stream insertion operator E) None of these
D
This statement may be used to stop a loop's current iteration and begin the next one. A) break B) terminate C) return D) continue E) None of these
D
To write data to a file, you define an object of this data type. A) outputFile B) ifstream C) fstream D) ofstream
D
What will the following code display? int x = 0; for (int count = 0; count < 3; count++) x += count; cout << x << endl; A) 0 1 2 B) 0 C) 6 D) 3
D
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 condition that is tested by a while loop must be enclosed in parentheses and terminated with a semicolon.
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: 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: 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: The update expression of a for loop can contain more than one statement, e.g. counter++, total+= sales.
TRUE
Assume a file stream object has been created when answering the following question. A file must be ________ to the file stream object before data can be written to or read from it. A) closed and unlinked B) opened and linked C) buffered and attached D) initialized and introduced
opened and linked
x = 0; if (++x) cout << "It is true! \n"; else cout << "It is false! \n";
It is true!
x = 99; if (x++ < 100) cout "It is true! \n"; else cout << "It is false! \n";
It is true!
If you place a semicolon after the test expression in a while loop, it is assumed to be a(n): A) pre-test loop B) post-test loop C) null statement D) infinite loop E) None of these
C
In a for statement, this expression is executed only once. A) test B) null C) initialization D) validation E) None of these
C
