CS 4A- Chapter 5 – Loops

Analyze the following code.

double sum = 0;
for (double d = 0; d < 10; sum += sum + d) {
d += 0.1;
}

The program compiles and runs fine.

What is the number of iterations in the following loop:

for (int i = 1; i < n; i++) {
// iteration
}

n – 1

Analyze the following statement:

double sum = 0;
for (double d = 0; d<10;) {
d += 0.1;
sum += sum + d;
}

The program compiles and runs fine.

The elements inside the for loop control are separated using semicolons instead of commas. True/False

True

What is the value in count after the following loop is executed?

int count = 0;
do {
System.out.println("Welcome to Java");
} while (count++ < 9);
System.out.println(count);

10

What is the output of the following fragment?

for (int i = 0; i < 15; i++) {
if (i % 4 == 1)
System.out.print(i + " ");
}

1 5 9 13

What is y after the following for loop statement is executed?

int y = 0;
for (int i = 0; i < 10; ++i) {
y += 1;
}

10

What is the output for y?

int y = 0;
for (int i = 0; i<10; ++i) {
y += i;
}
System.out.println(y);

45

A continue statement can be used only in a loop. True/False

True

A break statement can be used only in a loop. True/False

False

What is sum after the following loop terminates?

int sum = 0;
int item = 0;
do {
item++;
sum += item;
if (sum > 4) break;
}
while (item < 5);

6

Which of the following loops produces the following output? (choose all that apply)

1 2 3 4 1 2 3 1 2 1

(I)
for (int i = 5; i > 0; i–) {
for (int j = 1; j < i; j++)
System.out.print(j + " ");
System.out.println();
}

(II)
for (int i = 1; i < 5; i++) {
for (int j = 1; j < i; j++)
System.out.print(j + " ");
System.out.println();
}

(III)
int i = 0;
while (i < 5) {
for (int j = 1; j < i; j++)
System.out.print(j + " ");
System.out.println();
i++;
}

(IV)
int i = 5;
while (i > 0) {
for (int j = 1; j < i; j++)
System.out.print(j + " ");
System.out.println();
i–;
}

I & IV

A variable declared in the for loop control can be used after the loop exits. True/False

False

What is i after the following for loop?

int y = 0;
for (int i = 0; i<10; ++i) {
y += i;
}

Undefined

Do the following two statements in (I) and (II) result in the same value in sum?

(I):
for (int i = 0; i<10; ++i) {
sum += i;
}

(II):
for (int i = 0; i<10; i++) {
sum += i;
}

Yes

Is the following loop correct?

for (; ; );

Yes

You can always convert a for loop to a while loop. True/False

True

How many times will the following code print "Welcome to Java"?

int count = 0;
while (count++ < 10) {
System.out.println("Welcome to Java");
}

10

How many times are the following loops executed?

for (int i = 0; i < 10; i++)
for (int j = 0; j < i; j++)
System.out.println(i * j)

45

Suppose cond1 is a Boolean expression. When will this while condition be true?

while ( !cond1) …

If cond1 is false

Assume x is 0. What is the output of the following statement?

if (x > 0)
System.out.println("x is greater than 0");
else if (x < 0)
System.out.println("x is less than 0");
else
System.out.println("x equals 0");

x = 0

What is the output of the following code:

for ( ; false ; )
System.out.println("Welcome to Java");

Does not print anything

You can always convert a while loop to a for loop.

True

What is 1.0 + 1.0 + 1.0 == 3.0?

There is no guarantee that 1.0 + 1.0 + 1.0 == 3.0 is true.

How many times will the following code print "Welcome to Java"?

int count = 0;
while (count < 10) {
System.out.println("Welcome to Java");
count++;
}

10

Analyze the following fragment:

double sum = 0;
double d = 0;
while (d != 10.0) {
d += 0.1;
sum += sum + d;
}

The program may not stop because of the phenomenon referred to as numerical inaccuracy for operating with floating-point numbers.

Which of the following expression yields an integer between 0 and 100, inclusive?

(int)(Math.random() * 101)

How many times will the following code print "Welcome to Java"?

int count = 0;
do {
System.out.println("Welcome to Java");
count++;
} while (count < 10);

10

What is the value of balance after the following code is executed?

int balance = 10;

while (balance >= 1) {
if (balance < 9) break;
balance = balance – 9;
}

1

Analyze the following code.

int count = 0;
while (count < 100) {
// Point A
System.out.println("Welcome to Java!");
count++;
// Point B
}

// Point C

– count < 100 is always true at Point A – count < 100 is always false at Point C

What balance after the following code is executed?

int balance = 10;

while (balance &gt;= 1) {
if (balance &lt; 9) continue;
balance = balance – 9;
}

The loop does not end

How many times will the following code print "Welcome to Java"?

int count = 0;
do {
System.out.println("Welcome to Java");
} while (++count &lt; 10);

10

The while loop and the do loop are equivalent in their expressive power; in other words, you can rewrite a while loop using a do loop, and vice versa. True/False

True

What is the number of iterations in the following loop:

for (int i = 1; i &lt;= n; i++) {
// iteration
}

n

How many times will the following code print "Welcome to Java"?

int count = 0;
do {
System.out.println("Welcome to Java");
} while (count++ &lt; 10);

11

You can always write a program without using break or continue in a loop. True/False

True