Question 1

Consider a method named avg, which accepts four numbers as integers and returns their average as a double. Which of the following is a correct call to the method avg?

Accepted Answer

Option A is incorrect because it includes a double value, 3.14, while the method expects integer values. 
Option C is incorrect because the method expects four integer arguments, which are not provided. 
Option D is incorrect because it includes string values as arguments, while the method expects integer values. 
Hence, option B is the correct call to the method, where four integer values are passed, and the result is assigned to a double variable.

Question 2

Consider a method named calc, which accepts two numbers as integers and returns their sum as an integer. Which of the following is the correct statement to invoke the method calc?

Accepted Answer

Option A is incorrect because the second argument is a double, while the method only accepts integers. 
Option B is correct because it correctly calls the method calc with two integer arguments and assigns the result to the integer variable sum. 
Option C is incorrect because the method requires two integer arguments to be passed. 
Option D is incorrect because the method requires integer arguments, not string arguments.

Question 3

What is the output of the following code snippet?
Public static int recurrAverage(int num)
{
Int sum = 0;
For (int x = 1; x <= num; x++)
{
Sum = sum + x;
}
Return sum / num;
}
Public static void main(String[] args)
{
System.out.println(recurrAverage(recurrAverage(16)));
}

Accepted Answer

The function `recurrAverage` calculates the average of numbers from 1 to `num`. First, `recurrAverage(16)` returns 8, then `recurrAverage(8)` returns 4.

Question 4

What is the error in the following method definition?
public static int tripler(int numPara)
{
double result = numPara * 3;
}

Accepted Answer

The method declares a variable "result" but does not return it. It should have a return statement to return the value of "result".

Question 5

Consider this method comment. Which of the following options is recommended in your textbook?
/**
Computes the area of a cuboid.
@param width the width of the cuboid
@return the area of the cuboid
*/
Public static double area(double width, double height,
Double length)
{
Double result = width * height * length;
Return result;
}

Accepted Answer

According to the textbook, it is recommended to describe all the parameters in the method comment. Therefore, the parameter "height" and "length" also need to be described in the comment.

Question 6

What is the syntax error in the following method definition?
Public static String parameter(double r)
{
Double result;
Result = 2 * 3.14 * r;
Return result;
}

Accepted Answer

The method is supposed to return a String, but it attempts to return a Double, which is a type mismatch.

Question 7

In a vehicle mileage application, you enter number of miles traveled by a vehicle and the amount of fuel used for 30 consecutive days. From this data the average monthly mileage of the vehicle is calculated. Which of the following should be done to improve the program design?

Accepted Answer

Writing a method that returns the average monthly mileage as a double value would improve the program design as it would make the code more modular and reusable. It would also help in reducing errors and inconsistencies in the calculation of the average monthly mileage. Copy and paste can introduce errors, and repeating the same comment does not add any value to the program. Writing a method that returns void would be unnecessary as the program needs to return a value.

Question 8

What is the error in the following method definition?
Public static void findMin(int x, int y)
{
Int min = 0;
If (x < y)
{
Min = x;
}
Else
{
Min = y;
}
}

Accepted Answer

The method doesn't return any value, it simply assigns the minimum value to a local variable 'min'.

Question 9

The Java method Math.round can be used to round numbers. Which of the following code fragments converts a floating-point number to the nearest integer?

Accepted Answer

The Math.round method returns the closest long to the argument, so in order to get an integer we need to cast it to int. Option B ensures that the double f is rounded to the nearest integer value before being cast to an int.

Question 10

In an accounting application, you discover several places where the total profit, a double value, is calculated. Which of the following should be done to improve the program design?
I. The next time the total profit is calculated, use copy and paste to avoid making coding errors.
II. Provide the same comment every time you repeat the total profit calculation.
III. Consider writing a method that returns the total profit as a double value.

Accepted Answer

By writing a method to return the total profit as a double value, the code becomes more modular and easier to maintain in the future. Copy and pasting the same code can lead to errors and is not a scalable solution. Adding comments to the repeated code does not address the issue of duplication and maintainability.

Question 11

What is the output of the following code snippet?
Public static void doubleAmount(int intvalue)
{
Intvalue = 2 * intvalue;
}
Public static void main(String[] args)
{
Int principalAmt = 2000;
System.out.println(doubleAmount(principalAmt));
}

Accepted Answer

There are two errors in this code.

Firstly, the method doubleAmount() is declared as void, which means it does not return any value. Therefore, it cannot be printed using System.out.println().

Secondly, the variable name in the method signature (intvalue) does not match the variable name used in the method body (Intvalue). This will cause a compilation error.

Question 12

Suppose you need to write a method that calculates the volume of a 3D rectangular solid. Which of the following is the best choice for the declaration of this method?

Accepted Answer

Option B is the best choice for declaring the method because it takes in the width, height, and length parameters as doubles and returns the volume as a double. This allows for a more accurate calculation of the volume of the rectangular solid, and the return type of double ensures that the result is precise. Option A and C have void return types, which means they don't return anything, and option D only takes in the width as a parameter, which is not enough to calculate the volume of a rectangular solid.

Question 13

Which of the following options represents the output of the given code snippet?
Public static int addsub(int a, boolean isSub)
{
Return (isSub ? sub(a) : a + 1);
}
Public static int sub(int a) {
Return a - 1;
}
Public static void main(String[] args)
{
System.out.println("Sub 5 = " + addsub(5, true) +
", Add 6 = " + addsub(6, false));
}

Accepted Answer

When addsub(5, true) is called, it will return sub(5) which is 4.
When addsub(6, false) is called, it will return a+1 which is 7.

Therefore, the output will be "Sub 5 = 4, Add 6 = 7".

Question 14

Which of the following is true about methods?

Accepted Answer

Methods can have multiple arguments and can return one return value. It is possible to have more than one argument in a method as well as return only one value. However, having multiple return values is not possible in Java.

Question 15

Which of the following is not legal in a method definition?

Accepted Answer

Multiple return values are not legal in a method definition. A method can only have one return value.

Question 16

The Math.ceil method in the Java standard library takes a single value x and returns the smallest integer that is greater than or equal to x. Which of the following is true about Math.ceil(56.75)?

Accepted Answer

Math.ceil(56.75) takes 56.75 as an argument and returns the smallest integer that is greater than or equal to 56.75, which is 57. Therefore, the correct answer is A.

Question 17

What are the values of x and y after executing the code snippet below?
public static void swap(int a, int b) {
int t = a;
a = b;
b = t;
}
public static void main(String[] args)
{
int x = 10;
int y = 11;
swap(x, y);
}

Accepted Answer

The swap() method only swaps the values of its local variables a and b, not the values of x and y. Therefore, x remains 10 and y remains 11 after the swap() method is called.

Question 18

What are the values of num1 and num2 and result after executing the code snippet below?
Public static int mystery (int firstNum, int secondNum)
{
FirstNum = firstNum * 2;
SecondNum = secondNum * 3;
Return firstNum + secondNum;
}
Public static void main(String[] args)
{
Int num1 = 10;
Int num2 = 11;
Int result = mystery(num1, num2);
}

Accepted Answer

The method `mystery` modifies local copies of `firstNum` and `secondNum`, not the original `num1` and `num2`. Thus, `num1` and `num2` remain 10 and 11, respectively. The result is calculated as 20 + 33 = 53.

Question 19

What is the output of the following code snippet?
Public class test04
{
Public static int pow(int base, int power)
{
Int result = 1;
For (int i = 0; i < power; i++)
{
Result = result * base;
}
Return result;
}
Public static void main(String[] args)
{
System.out.println(pow(pow(2, 2), 2));
}
}

Accepted Answer

The inner pow(2,2) call will return 4, and then the outer pow(4,2) call will return 16. Therefore, the output will be 16.

Question 20

What can be used as an argument in a method call?
I. A variable
II. An expression
III. Another method call that returns a value
IV. Another method call that has no return value

Accepted Answer

All options I, II, and III can be used as arguments in a method call. Option IV, which refers to a method call with no return value, cannot be used as an argument in a method call because it does not produce a value that can be passed to another method.

Quiz 5: Methods

Consider a method named avg, which accepts four numbers as integers and returns their average as a double. Which of the following is a correct call to the method avg?

Consider a method named calc, which accepts two numbers as integers and returns their sum as an integer. Which of the following is the correct statement to invoke the method calc?

What is the output of the following code snippet? Public static int recurrAverage(int num) { Int sum = 0; For (int x = 1; x <= num; x++) { Sum = sum + x; } Return sum / num; } Public static void main(String[] args) { System.out.println(recurrAverage(recurrAverage(16) ) ) ; }

What is the error in the following method definition? public static int tripler(int numPara) { double result = numPara * 3; }

What is the syntax error in the following method definition? Public static String parameter(double r) { Double result; Result = 2 * 3.14 * r; Return result; }

In a vehicle mileage application, you enter number of miles traveled by a vehicle and the amount of fuel used for 30 consecutive days. From this data the average monthly mileage of the vehicle is calculated. Which of the following should be done to improve the program design?

What is the error in the following method definition? Public static void findMin(int x, int y) { Int min = 0; If (x < y) { Min = x; } Else { Min = y; } }

The Java method Math.round can be used to round numbers. Which of the following code fragments converts a floating-point number to the nearest integer?

What is the output of the following code snippet? Public static void doubleAmount(int intvalue) { Intvalue = 2 * intvalue; } Public static void main(String[] args) { Int principalAmt = 2000; System.out.println(doubleAmount(principalAmt) ) ; }

Suppose you need to write a method that calculates the volume of a 3D rectangular solid. Which of the following is the best choice for the declaration of this method?

Which of the following is true about methods?

Which of the following is not legal in a method definition?

The Math.ceil method in the Java standard library takes a single value x and returns the smallest integer that is greater than or equal to x. Which of the following is true about Math.ceil(56.75) ?

What are the values of x and y after executing the code snippet below? public static void swap(int a, int b) { int t = a; a = b; b = t; } public static void main(String[] args) { int x = 10; int y = 11; swap(x, y) ; }

What is the output of the following code snippet? Public class test04 { Public static int pow(int base, int power) { Int result = 1; For (int i = 0; i < power; i++) { Result = result * base; } Return result; } Public static void main(String[] args) { System.out.println(pow(pow(2, 2) , 2) ) ; } }

What can be used as an argument in a method call? I. A variable II. An expression III. Another method call that returns a value IV. Another method call that has no return value