C.S. 150 Chapter 5 (Control Structures II (Repetition))

For looping

A control statement for specifying iteration, which allows code to be executed repeatedly.

Infinite loop

A loop that continues to execute endlessly

EOF (End of File) controlled while loop

A while loop that continues to execute until the end-of-file marker is reached.

Suppose sum and numare intvariables, and the input is 1 5 6 3 -1. What is the output of the following code? sum = 0; cin>> num; while (num!= -1) { sum = sum + num; cin>> num; } cout<< sum << endl; A. 15 B. 14

A. 15

In ____ structures, the computer repeats particular statements a certain number of times depending on some condition(s). A. Looping B. Branching C. Selection D. sequence

A. Looping

What is the initial statement in the following for loop? int i; for (i = 1; i < 20; i++) cout << "Hello World"; cout << "!" << endl; A. i= 1; B. i< 20; C. i++; D. cout << "Hello World";

A. i = 1;

Which executes first in a do...while loop? A. the statement B. loop condition C. the expression D. update statement

A. the statement

sentinel-controlled while loop

Awhile loop that uses a sentinel value to end the loop.

Suppose j, sum, and num are int variables, and the input is 6 4 1 4 -1. What is the output of the code? sum = 0; cin >> num; for (int j = 1; j <= 3; j++) { sum = sum + num; cin >> num; } cout << sum << endl; A. 10 B. 11 C. 14 D. 15

B. 11

To generate a random number, you can use the function rand of the header file ____________________. A. fstream B. cstdlib C. cmath D. string

B. cstdlib

Which of the following loops is guaranteed to execute at least once? A. forloop B. do...while loop C. while loop

B. do...while loop

____ loops are called posttest loops. A. for loop B. do...while loop C. while loop

B. do...while loop

cin >> ch; while (cin) { cout << ch; cin >> ch; } This code is an example of a(n) ____ while loop. A. sentinel-controlled B. flag-controlled C. EOF-controlled D. counter-controlled

C. EOF-controlled

A(n) ____-controlled while loop uses a bool variable to control the loop. A. Counter B. Sentinel C. Flag D. eof

C. Flag

What is the output of the following C++ code? num = 10; while (num > 10) num = num - 2; cout << num << endl; A. 0 B. 6 C. 8 D. 10

D. 10

What is the output of the following C++ code? num = 10; while (num> 10) num= num-2; cout<< num<< endl; A. 0 B. 6 C. 7 D. 10

D. 10

What is the output of the following loop? count = 5; cout << 'St'; do { cout << 'o'; count--; } while (count <= 5) A. St B. Sto C. Stop D. This is an infinite loop.

D. This is an infinite loop

Which of the following is a repetition structure in C++? A. if B. switch C. while ... do D. do ... while

D. do...while

do-while loop

Executes as long as the condition is true. To avoid an infinite loop, body must contain a statement that makes the expression false

The following for loop executes 5 times. for (i= 0; i<=5; i++) cout<< i; True or False?

False

The statement in the body of a while loop acts as a decision maker, True or False?

False

break

To exit early from a loop • Can eliminate the use of certain (flag) variables. To skip the remainder of a switch structure

In a counter-controlled while loop, the loop control variable must be initialized before the loop. True or False?

True

In the case of the sentinel-controlled while loop, the first item is read before the while loop is entered. True or False?

True

The control statements in the for loop include the initial statement, loop condition, and update statement. True or False?

True

The following while loop terminates when j >= 20. j = 0; while (j < 20) j++; True or False?

True

The following while loop terminates when j >=20. j = 0; while (j < 20) { cout<< "Hi" << endl; j++; } True or False?

True

The number of iterations of a counter controlled loop is known in advance. True or False?

True

The output of the following C++ code is 2 3 4 5. n = 1; while (n < 5) { n++; cout<< n << " "; } True or False?

True

continue

Used in while, for, and do...while structures. It skips remaining statements and proceeds with the next iteration of the loop.

Nested control structure

Using a control structure within a control structure

Flag-controlled while loop

uses a Boolean variable to control the execution of the loop