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CH 3 quiz

Terms in this set (47)

<=
The "less than or equal to" comparison operator in Java is __________.
==
The equal comparison operator in Java is __________.
true
What is 1 + 1 + 1 + 1 + 1 == 5?
There is no guarantee that 1.0 + 1.0 + 1.0 + 1.0 + 1.0 == 5.0 is true.
What is 1.0 + 1.0 + 1.0 + 1.0 + 1.0 == 5.0?
a Boolean Literal
In Java, the word true is ________.
if (radius > 0) System.out.println(radius radius 3.14159);
Which of the following code displays the area of a circle if the radius is positive.
x < 0 and z > 0
Suppose x = 1, y = -1, and z = 1. What will be displayed by 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");
The program runs and displays It is even!.



Explanation: It is a common mistake to use the = operator in the condition test. What happens is that true is assigned to even when you write even = true. So even is true. The program compiles and runs fine and prints 'It is even!'.
Analyze the following code:

boolean even = false;
if (even = true) {
System.out.println("It is even!");
}
if (!isPrime = false)
Suppose isPrime is a boolean variable, which of the following is the correct and best statement for testing if isPrime is true.
x is 1
What is the output of the following code?

int x = 0;
if (x < 4) {
x = x + 1;
}
System.out.println("x is " + x);
The code displays nothing.
Analyze the following code.

boolean even = false;
if (even) {
System.out.println("It is even!");
}
just right
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");
Both Code 1 and Code 2 are correct, but Code 2 is better.
Analyze the following code:

Code 1:

int number = 45;
boolean even;

if (number % 2 == 0)
even = true;
else
even = false;

Code 2:

int number = 45;
boolean even = (number % 2 == 0);
Income is greater than 3000
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");
}
System.exit(0);
The __________ method immediately terminates the program.
ABCD
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 correct?
I:
if (age < 16)
System.out.println("Cannot get a driver's license");
if (age >= 16)
System.out.println("Can get a driver's license");

II:
if (age < 16)
System.out.println("Cannot get a driver's license");
else
System.out.println("Can get a driver's license");

III:
if (age < 16)
System.out.println("Cannot get a driver's license");
else if (age >= 16)
System.out.println("Can get a driver's license");

IV:
if (age < 16)
System.out.println("Cannot get a driver's license");
else if (age > 16)
System.out.println("Can get a driver's license");
else if (age == 16)
System.out.println("Can get a driver's license");
II
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?

I:
if (age < 16)
System.out.println("Cannot get a driver's license");
if (age >= 16)
System.out.println("Can get a driver's license");

II:
if (age < 16)
System.out.println("Cannot get a driver's license");
else
System.out.println("Can get a driver's license");

III:
if (age < 16)
System.out.println("Cannot get a driver's license");
else if (age >= 16)
System.out.println("Can get a driver's license");

IV:
if (age < 16)
System.out.println("Cannot get a driver's license");
else if (age > 16)
System.out.println("Can get a driver's license");
else if (age == 16)
System.out.println("Can get a driver's license");
Explanation: a: (3 => 4) should be (3 >= 4), d: (x = 0) should be (x == 0), and e: should be (-10 < x) && (x < 0)
Which of the Boolean expressions below is incorrect?

A. (true) && (3 => 4)
B. !(x > 0) && (x > 0)
C. (x > 0) || (x < 0)
D. (x != 0) || (x = 0)
E. (-10 < x < 0)
((x < 100) && (x > 1)) || (x < 0)
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?
x < 5 || y < 5
Assume x = 4 and y = 5, Which of the following is true?
x != 5
Assume x = 4, Which of the following is true?
!(x == y)
x != y
Assume x = 4 and y = 5, Which of the following is true?
! (x == y)
x > y || x < y
Which of the following is equivalent to x != y?
10Explanation: For the && operator, the right operand is not evaluated, if the left operand is evaluated as false.
Suppose x=10 and y=10. What is x after evaluating the expression (y > 10) && (x-- > 10)?
B. 10
Suppose x=10 and y=10 what is x after evaluating the expression (y > 10) && (x++ > 10).
(ch >= 'A' || ch <= 'Z')
To check whether a char variable ch is an uppercase letter, you write ___________.
The statement has compile errors because (x<100) & (x > 10) must be enclosed inside parentheses.
Analyze the following code:

if (x < 100) && (x > 10)
System.out.println("x is between 10 and 100");
F
What is the output of the following code?

char ch = 'F';
if (ch >= 'A' && ch <= 'Z')
System.out.println(ch);
2
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
What will be displayed by the following switch statement?

char ch = 'a';

switch (ch) {
case 'a':
case 'A':
System.out.print(ch); break;
case 'b':
case 'B':
System.out.print(ch); break;
case 'c':
case 'C':
System.out.print(ch); break;
case 'd':
case 'D':
System.out.print(ch);
}
b (because there is no break
What will be displayed by the following switch statement?

char ch = 'b';

switch (ch) {
case 'a':
System.out.print(ch);
case 'b':
System.out.print(ch);
case 'c':
System.out.print(ch);
case 'd':
System.out.print(ch);
}
The switch control variable cannot be double.
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;
}
-10
What is y after the following statement is executed?

x = 0;
y = (x > 0) ? 10 : -10;
All three are correct, but Code 3 is preferred.
Analyze the following code fragments that assign a boolean value to the variable even.

Code 1:
if (number % 2 == 0)
even = true;
else
even = false;

Code 2:
even = (number % 2 == 0) ? true: false;

Code 3:
even = number % 2 == 0;
false
What is the output of the following code?

boolean even = false;
System.out.println((even ? "true" : "false"));
ABCE
Which of the following are valid specifiers for the printf statement?
A. %4c
B. %10b
C. %6d
D. %8.2d
E. %10.2e
1234.6
The statement System.out.printf("%3.1f", 1234.56) outputs ___________.
1.2e+03
The statement System.out.printf("%3.1e", 1234.56) outputs ___________.
123456
The statement System.out.printf("%5d", 123456) outputs ___________.
****123456
The statement System.out.printf("%10s", "123456") outputs ___________. (Note: * represents a space)
System.out.printf("%3d %4.2f", number, Math.pow(number, 1.5));

The correct answer is C
Explanation: Math.pow(number, 1.5) is a floating-point value and must be formatted using the specifier f, not d. number is an int and must be formatted using the specifier d.
Suppse number contains integer value 4, which of the following statement is correct?

A. System.out.printf("%3d %4d", number, Math.pow(number, 1.5));
B. System.out.printf("%3d %4.2d", number, Math.pow(number, 1.5));
C. System.out.printf("%3d %4.2f", number, Math.pow(number, 1.5));
D. System.out.printf("%3f %4.2d", number, Math.pow(number, 1.5));
E. System.out.printf("%3f %4.2f", number, Math.pow(number, 1.5));
i is an integer, but the format specifier %5.1f specifies a format for double value. The code has an error.
Analyze the following code:

int i = 3434; double d = 3434;
System.out.printf("%5.1f %5.1f", i, d);
*, +, &&, ||
The order of the precedence (from high to low) of the operators binary +, *, &&, || is:
y is 2 because x + 1 is assigned to x and then x is assigned to y.
What is y displayed in the following code?

public class Test1 {
public static void main(String[] args) {
int x = 1;
int y = x = x + 1;
System.out.println("y is " + y);
}
}
=
Which of the following operators are right-associative.
true
What is the value of the following expression?
true || true && false
(x > 0 && x < 10) is same as ((x > 0) && (x < 10))
B. (x > 0 || x < 10) is same as ((x > 0) || (x < 10))
C. (x > 0 || x < 10 && y < 0) is same as (x > 0 || (x < 10 && y < 0))
Which of the following statements are true?
A. (x > 0 && x < 10) is same as ((x > 0) && (x < 10))
B. (x > 0 || x < 10) is same as ((x > 0) || (x < 10))
C. (x > 0 || x < 10 && y < 0) is same as (x > 0 || (x < 10 && y < 0))
D. (x > 0 || x < 10 && y < 0) is same as ((x > 0 || x < 10) && y < 0)
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