Test 1

Question 1

Which of the following code displays the area of a circle if the radius is positive?

Answer 1

if (radius > 0) System.out.println(radius * radius * 3.14159);

Question 2

Suppose income is 4001, what is the output of the following code?
if (income > 3000) {
System.out.println(“Income is greater than 3000”);}
else if (income > 4000) {
System.out.println(“Income is greater than 4000”);}

Answer 2

Income is greater than 3000

Question 3

Analyze the following code.
int x = 0;
if (x > 0); {
System.out.println(“x”);
}

Answer 3

The symbol x is always printed.

Question 4

The following code displays ___________.
double temperature = 50;
if (temperature >= 100) System.out.println(“too hot”);
else if (temperature <= 40) System.out.println(“too cold”);
else System.out.println(“just right”);

Answer 4

just right

Question 5

The extension name of a Java source code file is:

Answer 5

java

Question 6

Suppose you write the code to display “Cannot get a driver’s license” if age is less than 16 and “Can get a driver’s license” if age is greater than or equal to 16. Which of the following code is the best?

Answer 6

if (age < 16) System.out.println(“Cannot get a driver’s license”);
else System.out.println(“Can get a driver’s license”);

Question 7

What is the printout of the following code fragment?
double x = 5.5;
int y = (int)x;
System.out.println(“x is “ + x + “ and y is “ + y) ;

Answer 7

x is 5.5 and y is 5

Question 8

Suppose x = 1, y = -1, and z = 1. What is the printout of the following statement?
if (x > 0)
if (y > 0)
System.out.println(“x > 0 and y > 0”);
else if (z > 0)
System.out.println(“x < 0 and z > 0”);

Answer 8

x < 0 and z > 0

Question 9

Which of the following assignment statements is illegal?

Answer 9

int t = 4.5;

Question 10

If a program compiles fine, but it produces incorrect result, then the program suffers __________.

Answer 10

logical error

Question 11

The expression “Java “ + 1 + 2 + 3 evaluates to ________.

Answer 11

Java 123

Question 12

What is the value of (double) (5/2)?

Answer 12

2.0

Question 13

What is the printout of the following code?
double x = 10.1;
int y = (int)x;
System.out.println(“x is “ + x + “ and y is “ + y);

Answer 13

x is 10.1 and y is 10

Question 14

Analyze the following code:
if (x < 100) && (x > 10)
System.out.println(“x is between 10 and 100”);

Answer 14

The statement has compile errors because (x<100) && (x > 10) must be enclosed inside parentheses.

Question 15

Suppose s is a string with the value “program”, char x = s.charAt(4) will return __________.

Answer 15

‘r’

Question 16

To assign a double variable d to an int variable x, you write

Answer 16

x = (int)d;

Question 17

What is the exact output of the following code?
double area = 3.5;
System.out.print(“area”);
System.out.print(area);

Answer 17

area3.5

Question 18

Analyze the following code.
boolean even = false;
if (even) { System.out.println(“It is even!”);}

Answer 18

The code displays nothing.

Question 19

What method do you use to read an int value?

Answer 19

input.nextInt();