CSC Chapter 3

Analyze the following code: Code 1: int number = 45; boolean even; if (number % 2 == 0) even = true; else even = false; Code 2: boolean even = (number % 2 == 0); a. Code 1 has compile errors. b. Code 2 has compile errors. c. Both Code 1 and Code 2 have compile errors. d. Both Code 1 and Code 2 are correct, but Code 2 is better.

Both Code 1 and Code 2 are correct, but Code 2 is better.

Which of the following is equivalent to x != y? a. ! (x == y) b. x > y && x < y c. x > y || x < y d. x >= y || x <= y

!(x == y) x > y || x < y

Which of the following is the correct expression that evaluates to true if the number x is between 1 and 100 or the number is negative? a. 1 < x < 100 && x < 0 b. ((x < 100) && (x > 1)) || (x < 0) c. ((x < 100) && (x > 1)) && (x < 0) d. (1 > x > 100) || (x < 0)

((x < 100) && (x > 1)) || (x < 0)

Which of the Boolean expressions below are incorrect? a. (true) && (3 => 4) b. !(x > 0) && (x > 0) c. (x > 0) || (x < 0) d. (x != 0) || (x = 0) e. (-10 < x < 0)

(true) && (3 => 4) (x != 0) || (x = 0) (-10 < x < 0)

Suppose x=10 and y=10 what is x after evaluating the expression (y >= 10) || (x++ > 10). a. 9 b. 10 c. 11

10

What is y after the following switch statement is executed? int x = 3; int y = 4; switch (x + 3) { case 6: y = 0; case 7: y = 1; default: y += 1; } a. 1 b. 2 c. 3 d. 4 e. 0

2

The "less than or equal to" comparison operator in Java is __________. a. < b. <= c. =< d. << e. !=

<=

The equal comparison operator in Java is __________. a. <> b. != c. == d. ^=

==

Analyze the following code: boolean even = false; if (even = true) { System.out.println("It is even!");} a. The program has a compile error. b. The program has a runtime error. c. The program runs fine, but displays nothing. d. The program runs fine and displays It is even!.

The program runs fine and displays It is even!.

Analyze the following code: if (x < 100) && (x > 10) System.out.println("x is between 10 and 100"); a. The statement has compile errors because (x<100) & (x > 10) must be enclosed inside parentheses. b. The statement has compile errors because (x<100) & (x > 10) must be enclosed inside parentheses and the println(Ö) statement must be put inside a block. c. The statement compiles fine.d.The statement compiles fine, but has a runtime error.

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

Analyze the following program fragment: int x; double d = 1.5; switch (d) { case 1.0: x = 1; case 1.5: x = 2; case 2.0: x = 3; } a. The program has a compile error because the required break statement is missing in the switch statement. b. The program has a compile error because the required default case is missing in the switch statement. c. The switch control variable cannot be double. d. No errors.

The switch control variable cannot be double

What is 1 - 1.0 - 1.0 - 1.0 - 1.0 - 1.0 == 5.0? a. true b. false c. There is no guarantee that 1 - 1.0 - 1.0 - 1.0 - 1.0 - 1.0 == 5.0 is true.

There is no guarantee that 1 - 1.0 - 1.0 - 1.0 - 1.0 - 1.0 == 5.0 is true.

In Java, the word true is ________. a. a Java keyword b. a Boolean literal c. same as value 1 d. same as value 0

a Boolean literal

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"); a. too hot b. too cold c. just right d. too hot too cold just right

just right

What is 1 + 1 + 1 + 1 + 1 == 5? a. true b. false c. There is no guarantee that 1 + 1 + 1 + 1 + 1 == 5 is true.

true

Suppose x = 1, y = -1, and z = 1. What is the printout of the following statement? (Please indent the statement correctly first.) 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"); a. x > 0 and y > 0; b. x < 0 and z > 0; c. x < 0 and z < 0; d. no printout.

x < 0 and z > 0;

Assume x = 4 and y = 5, Which of the following is true? a. x < 5 && y < 5 b. x < 5 || y < 5 c. x > 5 && y > 5 d. x > 5 || y > 5

x < 5 || y < 5

What is y after the following statement is executed? x = 0; y = (x > 0) ? 10 : -10; a. -10 b. 0 c. 10 d. 20 e. Illegal expression

-10

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"); a. no output b. Income is greater than 3000 c. Income is greater than 3000 followed by Income is greater than 4000 d. Income is greater than 4000 e. Income is greater than 4000 followed by Income is greater than 3000

Income is greater than 3000

14. The __________ method immediately terminates the program. a. System.terminate(0); b. System.halt(0); c. System.exit(0); d. System.quit(0); e. System.stop(0);

System.exit(0);

Analyze the following code. boolean even = false; if (even) { System.out.println("It is even!"); } a. The code displays It is even! b. The code displays nothing. c. The code is wrong. You should replace if (even) with if (even == true) d. The code is wrong. You should replace if (even) with if (even = true)

The code displays nothing

What is the output of the following code? boolean even = false; System.out.println((even ? "true" : "false")); a. true b. false c. nothing d. true false

false

Suppose isPrime is a boolean variable, which of the following is the correct and best statement for testing if isPrime is true. a. if (isPrime = true) b. if (isPrime == true) c. if (isPrime) d. if (!isPrime = false) e. if (!isPrime == false)

if (isPrime)