Unit 1 (Primitive Types)

Question 1

How do you print a variable? (x is predefined)

a) System.print(x);
b) System.out.print(x);
c) System.out(x);
d) System.out.print(x)

Answer 1

B. This is because in Java, you must include the calling of the System, the direction of input or output, and the print statement. D does fit the criteria but does not include a semicolon, a necessary form of syntax to define the end of a line or function.

Question 2

How do you print a string?
A) System.out.print(“This is a statement”);
B) System.out.print(This is a statement);
C) System.print(This is a statement);
D) system.out(“This is a statement”);
E) system.out.print(“This is a statement”);

Answer 2

A. This is because in Java, you must include the calling of the System, the direction of input or output, and the print statement. Quotations must also be included as they define the string.

Question 3

Consider the following code segment.

System.out.print(“AP”);
System.out.println();
System.out.println(“CS”);
System.out.print(“A”);

What is printed as a result of executing the code segment?

A) APCSA

B) APCS
A

C) AP
CSA

D)AP
CS
A

E) AP
CS
A

Answer 3

D.

Question 4

Consider the following code segment.

System.out.print(I do not fear computers. );   // Line 1
System.out.println(I fear the lack of them.);  // Line 2
System.out.println(--Isaac Asimov);            // Line 3

The code segment is intended to produce the following output but may not work as intended.

I do not fear computers. I fear the lack of them.
--Isaac Asimov

Which change, if any, can be made so that the code segment produces the intended output?

A) In line 1, print should be changed to println.

B) In lines 2 and 3, println should be changed to print.

C) The statement System.out.println() should be inserted between lines 2 and 3.

D) In lines 1, 2, and 3, the text that appears in parentheses should be enclosed in quotation marks.

E) No change is needed; the code segment works correctly as is.

Answer 4

Answer D
Correct. For the text that appears in parentheses to be interpreted as string literals, it must be enclosed in quotation marks.

Question 5

Consider the following code segment.

System.out.print("*");
System.out.println("**");
System.out.println("***");
System.out.print("****");

What is printed as a result of executing the code segment?

A) *
**
***
**

B) *
**
***

C) *
*****
**

D) **
**
**

E) **
**

Answer 5

Answer D.
Correct. The arguments of the first and second statements appear on the first line of output, since the print statement in line 1 of the code segment does not move the cursor to the next line before the println statement in line 2 of the code segment is executed. This produces a line of output containing ** and then moves the cursor to the next line. The println statement in line 3 of the code segment produces another line of output containing ** and then moves the cursor to the next line. The final print statement produces a third line of output that contains **.

Question 6

What is the * symbol?

Answer 6

Multiplication of doubles or ints

Question 7

What is the ++ operator

Answer 7

adds 1 to variable

Question 8

What is the – operator

Answer 8

subtracts 1 from a variable

Question 9

What is the % operator

Answer 9

It is the modulo operator. It works as division but returns a remainder, not the quotient.

Question 10

What is the / operator

Answer 10

The division operator. It returns a quotient

Question 11

What is the result? Look carefully.

int x = 4;
int y = 3;
int z = y%x;
System.out.print(z);

Answer 11

3

Question 12

What is the result? Look carefully.

int x = 4;
int y = 3;
int z = x%y;
System.out.print(z);

Answer 12

1

Question 13

What are the Unary Operators?

Answer 13

Increment, Decrement, negation, affirmation

Question 14

What is the priority tiering of the operators?

Answer 14

Parentheses
Unary operators
Multiplicative and fractional (*, /, %)
Additive and subtractive (+,-)

Question 15

What is the sequence of operators?

Answer 15

left to right with the priority going first.

Question 16

What is the result and explain?

int x = 3;
double y = 5;

double z = y/x;
double w = (int) y/x;
double v = (int)(y/x);
int m = y/x;
System.out.print(z+”, “+ w+”, “+v+”, “+m);

Answer 16

Output:

1.66666, 1.0, 1.0, 1

Explanation:

This is because when dividing double by int or vice versa, you will always get a double as an answer as the output is promoted to the class of double. Then, when cast as type int, it will truncate the result and make it 1. If it is then further defined as a double, it will become 1.0.

Question 17

how can you assign multiple variables in one line?

Answer 17

int a = 1, b = 2, c = 3;
OR
double a = 1, b = 2, c = 3;

Question 18

what are the restrictions on naming variables?

Answer 18

Cannot use Java Keywords
No spaces
Camel Case (ex. firstNameNum)

Question 19

Name all the java keywords

Answer 19

abstract, assert, boolean, break, byte, case, catch, char, class, const, continue, default, double, do, else, enum, extends, false, final, finally, float, for, goto, if, implements, import, instanceof, int, interface, long, native, new, null, package, private, protected, public, return, short, static, strictfp, super, switch, synchronized, this, throw, throws, transient, true, try, void, volatile, while

Question 20

What is wrong with this code segment?

double x = 3;
int y = 5;

int w = y/x;
System.out.print(w);

Answer 20

The operation of y/x must be cast to int because the value is assigned to double and must be cast to int. So, the operation should look like this:

int w = (int)(y/x)

This is because y is already an int and the whole operation must be enclosed in parentheses to make the code work. Or, you can also use this snippet as x is a double so it will make int/int division.

int w = y/(int)x

Question 21

say the main method.

Answer 21

public static void main(String[] args)
{

}

Question 22

Say the class method.

Answer 22

public class Main{
public static void main(String[] args)
{

} }

Question 23

What is an operand?

Answer 23

The things being operated on. Ex.
int x = 1, y = 2;
int w = x/y;

Here, x and y are the operands. The operator is the /