Misconceptions Check

What do you use to compare Strings?

• =

• ==

• .equals()

• &&

Answer explanation

= is for assigning values

== is for comparing primitive types (int, double, boolean, char)

.equals() is for comparing Objects/Strings

What do you use to compare ints and doubles?

• =

• ==

• .equals()

• ||

Answer explanation

= is for assigning values

== is for comparing primitive types (int, double, boolean, char)

.equals() is for comparing Objects/Strings

What do you use to compare chars and booleans?

• =

• ==

• .equals()

• !

Answer explanation

= is for assigning values

== is for comparing primitive types (int, double, boolean, char)

.equals() is for comparing Objects/Strings

Which of the following the correct way to initialize a String variable?

• string str = "Monday";

• String str = "Monday";

• String str = 'Monday';

• string str = 'Monday';

Answer explanation

String is a java class, unlike the primitive types (int, double, float, char). All classes should start with an uppercase letter. You know a String is a class because it has its own methods.

The indexes of elements in a Java array always start with _.

• 0

• 1

• 2

• 3

Answer explanation

When you construct an array int [] arr = new int[ 10 ] ; 10 refers to the length, which is the number of elements in the array. The index of those elements begins with 0.

What is the length of this String: "Bread"

• 2

• 3

• 4

• 5

Answer explanation

The length of a string is the number of characters in it. The index is the position of any character or set of characters within the string. Length starts counting with 1 and index starts with 0.

What index number is the "d" in the String: "Bread"

• 2

• 3

• 4

• 5

Answer explanation

The length of a string is the number of characters in it. The index is the position of any character or set of characters within the string. Length starts counting with 1 and index starts with 0.

Which of the following is a situation where you SHOULD use a For Each loop?

• When there is no need for an index because you are just going through loop forward through each element.

• When you need an index so that you can tell the loop to traverse backwards through the elements.

• When you would like to use the index to skip around the elements in the array.

• When you would like to mutate (change) elements in the array.

Answer explanation

For Each Loop:

Advantages

^{The possibility of programming error is eliminated.}

^{It makes the code more readable.}

^{There is no use of index or rather a counter in this loop.}

Disadvantages

^{It cannot traverse through the elements in reverse fashion.}

^{You cannot skip any element as the concept of index is not there.}

^{You cannot choose to traverse to odd or even indexed elements too.}

When using printf for formatting which format specifier is used for ints?

• %d

• %f

• %s

• %c

Answer explanation

%c character

%d decimal (integer)

%f floating-point / double

%s string of chars

When using printf for formatting which format specifier is used for doubles?

• %d

• %f

• %s

• %i

Answer explanation

%c character

%d decimal (integer)

%f floating-point / double

%s string of chars