Chapter 2 Operators And Statements

Question 1

A Java operator is

Answer 1

a special symbol that can be applied to a set of variables, values or
literals—referred to as operands—and that returns a result.

Question 2

Name the three flavors of operators in Java

Answer 2

unary
binary
ternary

Question 3

Java operators follow

Answer 3

order of operation, by decreasing order of operator precedence

Question 4

Java guarantees left-to-right evaluation if

Answer 4

two operators have the same level of precedence

Question 5

What type of operators: expression++, expression–

Answer 5

Post-unary operators

Question 6

What type of operators: ++expression, –expression

Answer 6

Pre-unary operators

Question 7

What type of operators: +, -, !

Answer 7

Other unary operators

Question 8

What type of operators: *, /, %

Answer 8

Multiplication/Division/Modulus

Question 9

What type of operators: +, -

Answer 9

Addition/Subtraction

Question 10

What type of operators: <>,&raquo_space;>

Answer 10

Shift operators

Question 11

What type of operators: , <=, >=, instanceof

Answer 11

Relational operators

Question 12

What type of operators: ==, !=

Answer 12

Equal to/not equal to

Question 13

What type of operators: &, ^, |

Answer 13

Logical operators

Question 14

What type of operators: &&, ||

Answer 14

Short-circuit logical operators

Question 15

What type of operators: boolean expression ? expression1 : expression2

Answer 15

Ternary operators

Question 16

What type of operators: =, +=, -=, *=, /=, %=, &=, ^=, !=, «=,&raquo_space;=,&raquo_space;>=

Answer 16

Assignment operators

Question 17

binary operators can be used to

Answer 17

perform mathematical operations on variables,

create logical expressions, as well as perform basic variable assignments.

Question 18

Can you use modulus operations on negative integers and floating point integers?

Answer 18

Yes

Question 19

Numeric promotion

Answer 19

1. If two values have different data types, Java will automatically promote one of the values
   to the larger of the two data types.
2. If one of the values is integral and the other is floating-point, Java will automatically
   promote the integral value to the floating-point value’s data type.
3. Smaller data types, namely byte, short, and char, are first promoted to int any time
   they’re used with a Java binary arithmetic operator, even if neither of the operands is
   int.
4. After all promotion has occurred and the operands have the same data type, the resulting
   value will have the same data type as its promoted operands.

Question 20

What is the data type of x * y?
int x = 1;
long y = 33;

Answer 20

If we follow the fi rst rule, since one of the values is long and the other is int, and long is larger than int, then the int value is promoted to a long, and the resulting value is long.

Question 21

What is the data type of x + y?
double x = 39.21;
float y = 2.1;

Answer 21

This is actually a trick question, as this code will not compile! Floating-point literals are assumed to be double, unless postfixed with an f, as in 2.1f. If the value was set properly to 2.1f, then the promotion would be
similar to the last example, with both operands being promoted to a double, and the result would be a double value.

Question 22

What is the data type of x / y?
short x = 10;
short y = 3;

Answer 22

In this case, we must apply the third rule, namely that x and y will both be promoted
to int before the operation, resulting in an output of type int. Pay close attention to
the fact that the resulting output is not a short

Question 23

What is the data type of x * y / z?
short x = 14;
float y = 13;
double z = 30;

Answer 23

First, x will automatically be promoted to
int solely because it is a short and it is being used in an arithmetic binary operation. The promoted x value will then be automatically promoted to a float so that it can be multiplied with y. The result of x * y will then be automatically promoted to a double, so that it can be multiplied with z, resulting in a double value.

Question 24

By definition, a unary operator is one that requires

Answer 24

exactly one operand, or variable, to function.

Question 25

[Blank} Unary operator
Indicates a number is positive, although numbers are assumed to be positive in Java unless accompanied by a negative unary operator

Answer 25

+

Question 26

[Blank] Unary operator

Indicates a literal number is negative or negates an expression

Answer 26

-

Question 27

[Blank] Unary operator

Increments a value by 1

Answer 27

++

Question 28

[Blank] Unary operator

Decrements a value by 1

Answer 28

–

Question 29

[Blank] Unary operator

Inverts a Boolean’s logical value

Answer 29

!

Question 30

The [Blank] flips the value of a boolean expression.

Answer 30

logical complement operator, !,

Question 31

Likewise, [Blank] reverses the sign of a numeric expression

Answer 31

the negation operator, -

Question 32

An assignment operator

Answer 32

is a binary operator that modifies, or assigns, the variable on the left-hand side of the operator, with the result of the value on the right-hand side of the equation.

Question 33

[Blank] is when a number is so large that it will no longer fit within the data type, so the system “wraps around” to the next lowest value and counts up from there.

Answer 33

Overflow

Question 34

[Blank] when the number is too low to fit in the data type.

Answer 34

Underflow

Question 35

System.out.print(2147483647+1);

Answer 35

-2147483648 (Overflow)

Question 36

[Blank] compare two expressions and return a

boolean value.

Answer 36

Relational Operators

Question 37

Name of relational operator:

Answer 37

Strictly Less Than

Question 38

Name of relational operator: <=

Answer 38

Less than or equal to

Question 39

Name of relational operator: >

Answer 39

Strictly Greater Than

Question 40

Name of relational operator: >=

Answer 40

Greater Than or Equal To

Question 41

Logical operators: & AND is only true if

Answer 41

both operands are true

Question 42

Logical operators: | Inclusive OR is only false if

Answer 42

both operands are false

Question 43

Logical operators: ^ Exclusive OR is only true if

Answer 43

the operands are different

Question 44

[Blank] is a complex decision-making structure

in which a single value is evaluated and flow is redirected to the first matching branch, known as a case statement.

Answer 44

A switch statement

Question 45

Data types supported by the switch statement are:

Answer 45

■ int and Integer
■ byte and Byte
■ short and Short
■ char and Character
■ int and Integer
■ String
■ enum values

Question 46

What is the output:
int dayOfWeek = 5;
switch(dayOfWeek) {
case 0:
System.out.println("Sunday");
default:
System.out.println("Weekday");
case 6:
System.out.println("Saturday");
break;
}

Answer 46

The code will jump to the default block and then execute all of the proceeding case statements in order until it finds a break statement or finishes the structure:
Weekday
Saturday

Question 47

A [Blank] transfers the flow of control out to the enclosing statement.

Answer 47

break statement

Question 48

A [Blank] causes fl ow to finish the execution of the current loop.

Answer 48

continue statement

Question 49

Which of the following Java operators can be used with boolean variables? (Choose all that
apply)
A. ==
B. +
C. --
D. !
E. %
F. <=

Answer 49

A, D. Option A is the equality operator and can be used on numeric primitives, boolean
values, and object references. Options B and C are both arithmetic operators and
cannot be applied to a boolean value. Option D is the logical complement operator
and is used exclusively with boolean values. Option E is the modulus operator, which
can only be used with numeric primitives. Finally, option F is a relational operator that
compares the values of two numbers.

Question 50

What data type (or types) will allow the following code snippet to compile? (Choose all that
apply)
byte x = 5;
byte y = 10;
\_\_\_\_\_ z = x + y;
A. int
B. long
C. boolean
D. double
E. short
F. byte

Answer 50

A, B, D. The value x + y is automatically promoted to int, so int and data types that
can be promoted automatically from int will work. Options A, B, D are such data
types. Option C will not work because boolean is not a numeric data type. Options E
and F will not work without an explicit cast to a smaller data type.

Question 51

What is the output of the following application?
1: public class CompareValues {
2: public static void main(String[] args) {
3: int x = 0;
4: while(x++ < 10) {}
5: String message = x > 10 ? “Greater than” : false;
6: System.out.println(message+”,”+x);
7: }
8: }
A. Greater than,10
B. false,10
C. Greater than,11
D. false,11
E. The code will not compile because of line 4.
F. The code will not compile because of line 5.

Answer 51

F. In this example, the ternary operator has two expressions, one of them a String and
the other a boolean value. The ternary operator is permitted to have expressions that
don’t have matching types, but the key here is the assignment to the String reference.
The compiler knows how to assign the first expression value as a String, but the second
boolean expression cannot be set as a String; therefore, this line will not compile.

Question 52

What change would allow the following code snippet to compile? (Choose all that apply)
3: long x = 10;
4: int y = 2 * x;
A. No change; it compiles as is.
B. Cast x on line 4 to int.
C. Change the data type of x on line 3 to short.
D. Cast 2 * x on line 4 to int.
E. Change the data type of y on line 4 to short.
F. Change the data type of y on line 4 to long.

Answer 52

B, C, D, F. The code will not compile as is, so option A is not correct. The value 2 * x
is automatically promoted to long and cannot be automatically stored in y, which is
in an int value. Options B, C, and D solve this problem by reducing the long value to
int. Option E does not solve the problem and actually makes it worse by attempting
to place the value in a smaller data type. Option F solves the problem by increasing the
data type of the assignment so that long is allowed.

Question 53

What is the output of the following code snippet?
3: java.util.List list = new java.util.ArrayList();
4: list.add(10);
5: list.add(14);
6: for(int x : list) {
7: System.out.print(x + “, “);
8: break;
9: }
A. 10, 14,
B. 10, 14
C. 10,
D. The code will not compile because of line 7.
E. The code will not compile because of line 8.
F. The code contains an infinite loop and does not terminate.

Answer 53

C. This code does not contain any compilation errors or an infinite loop, so options D,
E, and F are incorrect. The break statement on line 8 causes the loop to execute once
and finish, so option C is the correct answer.

Question 54

What is the output of the following code snippet?
3: int x = 4;
4: long y = x * 4 - x++;
5: if(y<10) System.out.println(“Too Low”);
6: else System.out.println(“Just right”);
7: else System.out.println(“Too High”);
A. Too Low
B. Just Right
C. Too High
D. Compiles but throws a NullPointerException.
E. The code will not compile because of line 6.
F. The code will not compile because of line 7.

Answer 54

F. The code does not compile because two else statements cannot be chained together
without additional if-then statements, so the correct answer is option F. Option E is
incorrect as Line 6 by itself does not cause a problem, only when it is paired with Line
7. One way to fix this code so it compiles would be to add an if-then statement on
line 6. The other solution would be to remove line 7.

Question 55

What is the output of the following code?
1: public class TernaryTester {
2: public static void main(String[] args) {
3: int x = 5;
4: System.out.println(x > 2 ? x < 4 ? 10 : 8 : 7);
5: }}
A. 5
B. 4
C. 10
D. 8
E. 7
F. The code will not compile because of line 4.

Answer 55

D. As you learned in the section “Ternary Operator,” although parentheses are not
required, they do greatly increase code readability, such as the following equivalent
statement:
System.out.println((x > 2) ? ((x < 4) ? 10 : 8) : 7)
We apply the outside ternary operator fi rst, as it is possible the inner ternary expression
may never be evaluated. Since (x>2) is true, this reduces the problem to:
System.out.println((x < 4) ? 10 : 8)
Since x is greater than 2, the answer is 8, or option D in this case.

Question 56

What is the output of the following code snippet?
3: boolean x = true, z = true;
4: int y = 20;
5: x = (y != 10) ^ (z=false);
6: System.out.println(x+", "+y+", "+z);
A. true, 10, true
B. true, 20, false
C. false, 20, true
D. false, 20, false
E. false, 20, true
F. The code will not compile because of line 5.

Answer 56

B. This example is tricky because of the second assignment operator embedded in line
5. The expression (z=false) assigns the value false to z and returns false for the
entire expression. Since y does not equal 10, the left-hand side returns true; therefore,
the exclusive or (^) of the entire expression assigned to x is true. The output reflects
these assignments, with no change to y, so option B is the only correct answer. The
code compiles and runs without issue, so option F is not correct.

Question 57

How many times will the following code print “Hello World”?
3: for(int i=0; i<10 ; ) {
4: i = i++;
5: System.out.println(“Hello World”);
6: }
A. 9
B. 10
C. 11
D. The code will not compile because of line 3.
E. The code will not compile because of line 5.
F. The code contains an infinite loop and does not terminate.

Answer 57

F. In this example, the update statement of the for loop is missing, which is fine as the
statement is optional, so option D is incorrect. The expression inside the loop increments
i but then assigns i the old value. Therefore, i ends the loop with the same value that it starts with: 0. The loop will repeat infinitely, outputting the same statement over
and over again because i remains 0 after every iteration of the loop.

Question 58

What is the output of the following code?
3: byte a = 40, b = 50;
4: byte sum = (byte) a + b;
5: System.out.println(sum);
A. 40
B. 50
C. 90
D. The code will not compile because of line 4.
E. An undefined value.

Answer 58

D. Line 4 generates a possible loss of precision compiler error. The cast operator has
the highest precedence, so it is evaluated first, casting a to a byte. Then, the addition is
evaluated, causing both a and b to be promoted to int values. The value 90 is an int
and cannot be assigned to the byte sum without an explicit cast, so the code does not
compile. The code could be corrected with parentheses around (a + b), in which case
option C would be the correct answer.

Question 59

What is the output of the following code?
1: public class ArithmeticSample {
2: public static void main(String[] args) {
3: int x = 5 * 4 % 3;
4: System.out.println(x);
5: }}
A. 2
B. 3
C. 5
D. 6
E. The code will not compile because of line 3.

Answer 59

A. The * and % have the same operator precedence, so the expression is evaluated
from left-to-right. The result of 5 * 4 is 20, and 20 % 3 is 2 (20 divided by 3 is 18, the
remainder is 2). The output is 2 and option A is the correct answer.

Question 60

What is the output of the following code snippet?
3: int x = 0;
4: String s = null;
5: if(x == s) System.out.println(“Success”);
6: else System.out.println(“Failure”);
A. Success
B. Failure
C. The code will not compile because of line 4.
D. The code will not compile because of line 5.

Answer 60

D. The variable x is an int and s is a reference to a String object. The two data types
are incomparable because neither variable can be converted to the other variable’s type.
The compiler error occurs on line 5 when the comparison is attempted, so the answer
is option D.

Question 61

What is the output of the following code snippet?
3: int x1 = 50, x2 = 75;
4: boolean b = x1 >= x2;
5: if(b = true) System.out.println(“Success”);
6: else System.out.println(“Failure”);
A. Success
B. Failure
C. The code will not compile because of line 4.
D. The code will not compile because of line 5.

Answer 61

A. The code compiles successfully, so options C and D are incorrect. The value of b
after line 4 is false. However, the if-then statement on line 5 contains an assignment,
not a comparison. The variable b is assigned true on line 3, and the assignment operator
returns true, so line 5 executes and displays Success, so the answer is option A.

Question 62

What is the output of the following code snippet?
3: int c = 7;
4: int result = 4;
5: result += ++c;
6: System.out.println(result);
A. 8
B. 11
C. 12
D. 15
E. 16
F. The code will not compile because of line 5.

Answer 62

C. The code compiles successfully, so option F is incorrect. On line 5, the pre-increment
operator is used, so c is incremented to 4 and the new value is returned to the
expression. The value of result is computed by adding 4 to the original value of 8,
resulting in a new value of 12, which is output on line 6. Therefore, option C is the
correct answer.

Question 63

What is the output of the following code snippet?
3: int x = 1, y = 15;
4: while x < 10
5: y––;
6: x++;
7: System.out.println(x+”, “+y);
A. 10, 5
B. 10, 6
C. 11, 5
D. The code will not compile because of line 3.
E. The code will not compile because of line 4.
F. The code contains an infinite loop and does not terminate.

Answer 63

E. This is actually a much simpler problem than it appears to be. The while statement
on line 4 is missing parentheses, so the code will not compile, and option E is the correct
answer. If the parentheses were added, though, option F would be the correct
answer since the loop does not use curly braces to include x++ and the boolean expression
never changes. Finally, if curly braces were added around both expressions, the
output would be 10, 6 and option B would be correct.

Question 64

What is the output of the following code snippet?
3: do {
4: int y = 1;
5: System.out.print(y++ + “ “);
6: } while(y <= 10);
A. 1 2 3 4 5 6 7 8 9
B. 1 2 3 4 5 6 7 8 9 10
C. 1 2 3 4 5 6 7 8 9 10 11
D. The code will not compile because of line 6.
E. The code contains an infinite loop and does not terminate.

Answer 64

D. The variable y is declared within the body of the do-while statement, so it is out of
scope on line 6. Line 6 generates a compiler error, so option D is the correct answer.

Question 65

What is the output of the following code snippet?
3: boolean keepGoing = true;
4: int result = 15, i = 10;
5: do {
6: i--;
7: if(i==8) keepGoing = false;
8: result -= 2;
9: } while(keepGoing);
10: System.out.println(result);
A. 7
B. 9
C. 10
D. 11
E. 15
F. The code will not compile because of line 8.

Answer 65

D. The code compiles without issue, so option F is incorrect. After the first execution
of the loop, i is decremented to 9 and result to 13. Since i is not 8, keepGoing is
false, and the loop continues. On the next iteration, i is decremented to 8 and result
to 11. On the second execution, i does equal 8, so keepGoing is set to false. At the
conclusion of the loop, the loop terminates since keepGoing is no longer true. The
value of result is 11, and the correct answer is option D.

Question 66

What is the output of the following code snippet?
3: int count = 0;
4: ROW_LOOP: for(int row = 1; row <=3; row++)
5: for(int col = 1; col <=2 ; col++) {
6: if(row * col % 2 == 0) continue ROW_LOOP;
7: count++;
8: }
9: System.out.println(count);
A. 1
B. 2
C. 3
D. 4
E. 6
F. The code will not compile because of line 6.

Answer 66

A. The expression on line 5 is true when row * col is an even number. On the first
iteration, row = 1 and col = 1, so the expression on line 6 is false, the continue is
skipped, and count is incremented to 1. On the second iteration, row = 1 and col = 2, so the expression on line 6 is true and the continue ends the outer loop with
count still at 1. On the third iteration, row = 2 and col = 1, so the expression on line
6 is true and the continue ends the outer loop with count still at 1. On the fourth
iteration, row = 3 and col = 1, so the expression on line 6 is false, the continue is
skipped, and count is incremented to 2. Finally, on the fifth and final iteration, row
= 3 and col = 2, so the expression on line 6 is true and the continue ends the outer
loop with count still at 2. The result of 2 is displayed, so the answer is option B.

Question 67

What is the result of the following code snippet?
3: int m = 9, n = 1, x = 0;
4: while(m > n) {
5: m--;
6: n += 2;
7: x += m + n;
8: }
9: System.out.println(x);
A. 11
B. 13
C. 23
D. 36
E. 50
F. The code will not compile because of line 7.

Answer 67

D. Prior to the first iteration, m = 9, n = 1, and x = 0. After the iteration of the first
loop, m is updated to 8, n to 3, and x to the sum of the new values for m + n, 0 + 11 =
11. After the iteration of the second loop, m is updated to 7, n to 5, and x to the sum
of the new values for m + n, 11 + 12 = 23. After the iteration of the third loop, m is
updated to 6, n to 7, and x to the sum of the new values for m + n, 23 + 13 = 36. On
the fourth iteration of the loop, m > n evaluates to false, as 6 < 7 is not true. The
loop ends and the most recent value of x, 36, is output, so the correct answer is option
D.

Question 68

What is the result of the following code snippet?
3: final char a = ‘A’, d = ‘D’;
4: char grade = ‘B’;
5: switch(grade) {
6: case a:
7: case ‘B’: System.out.print(“great”);
8: case ‘C’: System.out.print(“good”); break;
9: case d:
10: case ‘F’: System.out.print(“not good”);
11: }
A. great
B. greatgood
C. The code will not compile because of line 3.
D. The code will not compile because of line 6.
E. The code will not compile because of lines 6 and 9.

Answer 68

B. The code compiles and runs without issue, so options C, D, and E are not correct. The
value of grade is ‘B’ and there is a matching case statement that will cause “great” to
be printed. There is no break statement after the case, though, so the next case statement
will be reached, and “good” will be printed. There is a break after this case statement,
though, so the switch statement will end. The correct answer is thus option B.