CS150 Module 5
What is the output of the following C++ code? num = 10; while (num > 10) num = num - 2; cout << num << endl;
10
What is the output of the following C++ code? int j; for (j = 10; j <= 10; j++) cout << j << " "; cout << j << endl;
10 11
Suppose j, sum, and num are int variables, and the input is 26 34 61 4 -1. What is the output of the code? sum = 0; cin >> num; for (int j = 1; j <= 4; j++) { sum = sum + num; cin >> num; } cout << sum << endl;
125
Suppose sum and num are int variables, 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;
15
What is the output of the following program segment? int count = 0; while (count++ < 5) cout << count + 1 << " "; cout << endl;
2 3 4 5 6
What is the output of the following C++ code? count = 1; num = 25; while (count < 25) { num = num - 1; count++; } cout << count << " " << num << endl;
25 1
What is the value of x after the following statements execute? int x = 5; int y = 30; do x = x * 2; while (x < y);
40
Consider the following code. (Assume that all variables are properly declared.) cin >> ch; while (cin) { cout << ch; cin >> ch; } This code is an example of a(n) ____ while loop.
EOF-controlled
Consider the following for loop. int j, s; s = 0; for (j =1; j<=10; j++) s = s + j * (j - 1); In this for loop, identify the loop control variable, the initialization statement, loop condition, the update statement, and the statement that updates the value of s.
Loop control variable-- j The initialization statement-- j = 1; Loop condition -- j<=10; Update statement -- j++ The statement that updates the value of s-- s + j * (j-1);
Suppose that the input is 0 5 6 4 9 8 -1. What is the output of the following code? int num = 0; int sum; cin >> sum; while (num != -1) { cin >> num; sum = sum + 2 * static_cast<int> (sqrt(num)); } cout << "Sum = " << sum << endl;
Sum = 22
What is the output of the following loop? count = 5; cout << 'St'; do { cout << 'o'; count--; } while (count <= 5);
This is an infinite loop.
The body of this loop executes at least once.
do...while
Which of the following is a repetition structure in C++?
do...while
Which of the following loops does not have an entry condition?
do...while loop
Which of the following loops is guaranteed to execute at least once?
do...while loop
What does a break statement do in a loop?
exits the loop
In a counter-controlled while loop, it is not necessary to initialize the loop control variable.
false
The statement in the body of a while loop acts as a decision maker.
false
When a while loop terminates, the control goes back to the statement just before the while statement, and then the control goes to the statement immediately following the while loop.
false
A(n) ____-controlled while loop uses a bool variable to control the loop.
flag
When does the following while loop terminate? char ch = 'D'; while ('A' <= ch && ch <= 'Z') ch = static_cast< char> (static_cst<int>(ch)+ 1;
if ch > 'Z' or ch < 'A'
A loop that continues to execute endlessly is called a(n) _________ loop.
infinite
In ____ structures, the computer repeats particular statements a certain number of times depending on some condition(s).
looping
In ____________ structures, the computer repeats particular statements a certain number of times depending on some condition(s).
looping
What is the output of the following program segment? int num = 0, count; int y=0; for (count = 1; count <= 5; ++ count) { y=y + count; num = num * count + y; } cout << "num = " << num << ", y = " << y << endl;
num= 485, y =15
A(n) ____ is an arbitrary value that, when read, stops the execution of a loop
sentinal
Suppose that the input is 20 -16 -5 15 6 0. What is the output of the following code? int num; int temp = 0; cin >> num; while ( num!= 0) { if (num % 2 == 0) temp = temp + num; else temp = temp - num; cin >> num; } cout << "temp = " << temp << endl;
temp = 0
Which executes first in a do... while loop?
the statement
A loop is a control structure that causes certain statements to execute over and over
true
A sentinel-controlled while loop is an event-controlled while loop whose termination depends on a special value.
true
Assume all variables are properly declared. The output of the following C++ code is 2 3 4 5. n = 1; while (n < 5) { n++; cout << n << " "; }
true
Both the while loop and the do...while loop are considered a conditional loop.
true
Executing a break statement in the body of a loop immediately terminates the loop.
true
In a counter-controlled while loop, the loop control variable must be initialized before the loop.
true
In an infinite loop, the while expression (the decision maker) is initially false, but after the first iteration it is always true. j = 0; while (j <= 10) j++; The while loop: terminates if j>10.
true
In the case of the sentinel-controlled while loop, the first item is read before the while loop is entered.
true
It is possible that the body of a while loop may not execute at all
true
The control statements in the for loop include the initial statement, loop condition, and update statement.
true
The control variable in a flag-controlled while loop is a bool variable.
true
The following while loop terminates when j>=20. j = 0; while (j < 20) j++;
true
The number of iterations of a counter-controlled loop is known in advance.
true
The output of the following C++ code is 2 3 4 5. n = 1; while (n < 5) { n++; cout << n << " "; }
true
To read data from a file of an unspecified length, an EOF-controlled loop is a good choice.
true
The body of the loop may not execute at all for the _________ loop.
while
Which loop has the logical expression controlling the loop and is evaluated before the loop is entered.
while
What is the output of the following program segment? int count = 0; while ( count++ <= 5) cout << (count -1) * (count -2) << " "; cout << endl;
0 3 8 15 24
What is the output of the following C++ code? num = 10; while (num > 10) { num = num -2; } cout << num << endl;
10
To generate a random number, you can use the function rand of the header file
cstdlib
A do...while loop is called a pretest loop.
false
