Question 1

Using the various String methods, manipulate a String called current to be the last character of current followed by the remainder of its characters in order, placing the result in a String called rearranged.

Accepted Answer

The answer of Using the various String methods, manipulate a...

Question 2

Given three int variables with the values a = 5, b = 7, and c = 12, what is the value of z after the following statement is executed? int z = (a * b - c) / a;

Accepted Answer

Using the order of operations, we first evaluate a * b which is 35. We then subtract c, giving us 23. Finally, we divide by a which is 5.

(35 - 12) / 5 = 23 / 5 = 4.6

Since z is an int variable, it will be truncated to the nearest integer, which in this case is 4. Therefore, the value of z is 4.

Question 3

As presented in the Software Failure section of the text, the root cause of the Mars Climate Orbiter problem was

Accepted Answer

The root cause of the Mars Climate Orbiter problem was a communication issue between subsystems, specifically a mismatch between the unit of measurement used by the spacecraft's navigation software and the ground software. This led to incorrect thruster firings and ultimately caused the spacecraft to enter Mars' atmosphere at too low an altitude and be destroyed. Cost, tracking, and atmospheric friction were not primary factors in this failure.

Question 4

Explain what the following statement computes:
int z = (int)Math.ceil(Math.sqrt(x)/Math.sqrt(y));

Accepted Answer

The answer of Explain what the following statement computes:
int z...

Question 5

Example Code Ch 02-2
import java.util.Scanner;
public class Questions33_34
{
public static void main(String[] args)
{
int x, y, z;
double average;
Scanner scan = new Scanner(System.in);
System.out.println("Enter an integer value");
x = scan.nextInt();
System.out.println("Enter another integer value");
y = scan.nextInt();
System.out.println("Enter a third integer value");
z = scan.nextInt();
average = (x + y + z) / 3;
System.out.println("The result of my calculation
is " + average);
}
}
-Refer to Example Code Ch 02-2. What is the output if x = 0, y = 1, and z = 1?

Accepted Answer

The calculation (x + y + z) / 3 with x = 0, y = 1, and z = 1 results in (0 + 1 + 1) / 3 = 2 / 3 = 0 when using integer division, but since the result is stored in a double variable, it is represented as 0.0.

Question 6

Given two points in an applet represented by the four int variables x1, y1, x2 and y2, write a paint method to draw a line between the two points and write the location of the two points next to the two points.

Accepted Answer

The answer of Given two points in an applet represented...

Question 7

Write an assignment statement to compute the gas mileage of a car where the int values milesTraveled and gallonsNeeded have already been input. The variable gasMileage needs to be declared and should be a double.

Accepted Answer

The answer of Write an assignment statement to compute the...

Question 8

How many ways are there to test to see if two String variables, a and b, are equal to each other if we ignore their case (for instance, "aBCd" would be considered equal to "ABcd")?

Accepted Answer

The answer of How many ways are there to test...

Question 9

Given four int values, x1, x2, y1, y2, write the code to compute the distance between the two points (x1, y1) and (x2, y2), storing the result in the double distance.

Accepted Answer

The answer of Given four int values, x1, x2, y1,...

Question 10

Write a set of instructions to prompt the user for an int value and input it using the Scanner class into the variable x and prompt the user for a float value and input it using the Scanner class into the variable y.

Accepted Answer

The answer of Write a set of instructions to prompt...

Question 11

How do the statements "import java.util.*;" and "import java.util.Random;" differ from each other?

Accepted Answer

The answer of How do the statements "import java.util.*;" and...

Question 12

Java is a strongly typed language. What is meant by "strongly typed"?

Accepted Answer

In a strongly typed language like Java, every variable has a single type associated with it throughout its existence in the program and the variable can only store values of that type. This means that once a variable is declared with a certain type, it cannot store values of another type, and the type of the variable cannot be changed during its existence in the program.

Question 13

Since you cannot take the square root of a negative number, which of the following could you use to find the square root of the variable x?

Accepted Answer

The Math.abs() method will return the absolute value of x, which will make it positive. Then, the Math.sqrt() method can be used to find the square root of x.

Question 14

Given x is a double and has the value 0.362491. To output this value as 36%, you could use the NumberFormat class with: NumberFormat nf = NumberFormat.getPercentInstance();
Which of the following statements then would output x as 36%?

Accepted Answer

The correct choice to output x as 36% using NumberFormat class is System.out.println(nf.format(x)), where nf is the NumberFormat instance created by calling NumberFormat.getPercentInstance(). Calling System.out.println(x) will simply output the value of x as 0.362491. Calling System.out.println(nf) will output the string representation of the nf object. Calling System.out.println(nf.x) is invalid syntax in Java. Finally, calling System.out.println(format(x)) is not valid since format is not a defined method or variable in this context.

Question 15

Write the paint method for an applet so that it contains 4 concentric circles (each circle is inside the previous circle), where the largest circle is bounded by a 400x400 box and the smallest is bounded by a 100x100 box. Each circle is centered on an applet that is 400x400. Make each circle a different color of your choice.

Accepted Answer

The answer of Write the paint method for an applet...

Question 16

Example Code Ch 02-2
import java.util.Scanner;
public class Questions33_34
{
public static void main(String[] args)
{
int x, y, z;
double average;
Scanner scan = new Scanner(System.in);
System.out.println("Enter an integer value");
x = scan.nextInt();
System.out.println("Enter another integer value");
y = scan.nextInt();
System.out.println("Enter a third integer value");
z = scan.nextInt();
average = (x + y + z) / 3;
System.out.println("The result of my calculation
is " + average);
}
}
-Refer to Example Code Ch 02-2. This code computes

Accepted Answer

The code correctly calculates the average of x, y, and z, but since the variables are integers, the result will be truncated to an integer. To get an accurate average as a double, one or more of the variables should be declared as a double or the calculation should include a conversion to double, such as (x + y + z) / 3.0.

Question 17

An employer has decided to award a weekly pay raise to all employees by taking the square root of the difference between his weight and the employee's weight. For instance, an employee who weighs 16 pounds less than the employer will get a $4 per week raise. The raise should be in whole dollars (an int). Assume that employerWeight and employeeWeight are both int variables that have been input. Write an assignment statement to compute the int value for raise.

Accepted Answer

The answer of An employer has decided to award a...

Question 18

Provide an example of how you might use a boolean, a float, a char, a String, and an int.

Accepted Answer

The answer of Provide an example of how you might...

Question 19

What will be the value of z after the following statement is executed? int z = 50 /10.00;

Accepted Answer

The division of an integer by a floating-point number (10.00) results in a floating-point number. Since `z` is declared as an `int`, attempting to assign a floating-point result to it without explicit casting will cause a compile-time error, not a run-time error.

Question 20

In order to create a constant, which of the following Java reserved words is used?

Accepted Answer

The reserved word used to create a constant in Java is "final". This keyword is used to declare a constant value that cannot be changed.

Quiz 2: Data and Expressions