Unit 3 Quiz Review- Boolean expressions and Operators

Which of the following examples as Java expressions would return true?

• 20 < 40

• 20>=20

• "Friend".equals("Friend")

• 20 <35 && 15 <= 15

• All of the above

Which of the following is a valid statement for comparison of the weight of three items declared as w1, w2, and w3 of double data type?

I. (w1.compareTo(w2)==0) && (w2.compareTo(w3)==0)

II. (w1 >= w2) && (w1 >= w3)

III. (w1.equals(w2)) && (w1.equals(w3)

IV. (w1 >= w2) || (w1>=w3)

• I only

• III only

• I and III

• II and IV

• II and III

Answer explanation

Relational operators are used to compare values. equals() and compareTo() are methods to compare objects.

You want to compare the names of employees at Switch Video Games and arrange them in ascending order to make search and filtering easier and faster.

Which of the following Java expression components would you use?

• >

• compareTo()

• <

• ==

• equals()

Answer explanation

The compareTo() method is the method that should be used to compare two String values.

A programmer needs to write a code for a login screen to access the learning resources of www.javaforstudents.com. There are two options to login to the portal:

enter registered user name

or

enter registered mobile number

Which operator should the programmer use to complete this task?

• &

• !

• |

• ||

• &&

Answer explanation

|| (OR) operator should be used by the programmer to fulfill one of the conditions to log in to the screen.

Consider the code segment.

System.out.println("Joe".compareTo("Harry"));

What will be the output of this code?

• -2

• compile time error

• -3

• 2

• 3

Answer explanation

This will compare both the Strings, and the result will be the difference between Joe and Harry, or 2.

Consider the code below written to compare two objects.

My m1 = new My();

My m2 = new My();

System.out.println(m1==m2);

What will be the output of the above code?

• false

• true

• 0

• 1

• -1

Answer explanation

The == operator checks for reference equality, and it will give false.

Which Boolean operator is represented in the shaded portion of the Venn diagram below?

• |

• ||

• &

• $

• &&

Answer explanation

The shaded portion in the given the Venn diagram is known as intersection and it is represented as && (AND) operator.

Which statement below is true for relational and logical operator?

• Logical operators can have boolean operands only.

• Relational operators can have boolean operands only.

• Both statements can be used to compare String values.

• Both statements can have int and double operands.

For relational and logical operators, both statements can return boolean values

• True

• False