CodeHS Quiz: Boolean Expressions and if Statements

Which of the following is NOT a relational operator?

1. 
   

• <

• ?

• ==

• >=

What does this Java expression evaluate to?

80 >= 80

1. 
   

• "true"

• true

• false

• This expression will error

Consider the code snippet below.

String name = "Karel"; String checkName = new String("Karel"); boolean nameMatches = name == checkName;

• true

• false

• Cannot be determined

What is the difference between == and =?

• == is used for assignment, while = is used to check for equality

• = is used for assignment, while == is used to check for equality.

• == assigns values to objects while = assigns values to primitives.

• There is no difference. These symbols can be used interchangeably.

Which of the following symbols is the “not equal” symbol?

• ==

• not =

• !=

• <>

Why do we use if statements in Java?

• To break out of some block of code

• 1. To do something only if a condition is true

• 1. To do something while a condition is true

• To repeat something for a fixed number of times

Which if statement is written properly?

• if (boolean expression): // code to execute // code to execute

• 1. if boolean expression { // code to execute // code to execute }

• 1. 
     

     if(boolean expression) { // code to execute // code to execute }

• 1. if boolean expression [ // code to execute // code to execute ]

What is the output of this program?

int phLevel = 9; if(phLevel < 7) { System.out.println("It is acidic!"); } if(phLevel > 7) { System.out.println("It is basic!"); } if(phLevel == 7) { System.out.println("It is neutral!"); }

1. 
   

• 1. It is acidic!

• It is basic!

• 1. It is neutral!

• 1. It is acidic!
     It is basic!
     It is neutral!

What is the output of this program?

int numTreeRings = 50; System.out.println("How old is the tree?"); if(numTreeRings > 10) { System.out.println("Still young!"); } if(numTreeRings > 40) { System.out.println("Pretty old!"); } if(numTreeRings > 150) { System.out.println("Very old!"); }

• How old is the tree?
  Still young!

• How old is the tree?

  Still young!

  Pretty old!

• How old is the tree?
  Very old!

• How old is the tree?
  Still young!
  Pretty old!
  Very old!

What is the output of this program?

int numTreeRings = 50; System.out.println("How old is the tree?"); if(numTreeRings < 20) { System.out.println("Still young!"); } if(numTreeRings < 50) { System.out.println("Pretty old!"); } if(numTreeRings < 100) { System.out.println("Very old!"); }

1. 
   

• How old is the tree?
  Still young!

• 1. 
     

     How old is the tree?
     Pretty old!
     Very old!

• How old is the tree?
  Very old!

• How old is the tree?
  Still young!
  Pretty old!
  Very old!