Question 1

What is the output of the following code snippet?
Public static int someMethod(int x)
{
Int result = 0;
If (x > 10)
{
Result = x;
}
Else
{
Result = someMethod(4 * x);
}
Return result;
}
Public static void main(String[] args)
{
System.out.println("someMethod(2) = " + someMethod(2));
}

Accepted Answer

When someMethod(2) is called, it will enter the else block since 2 is not greater than 10. It will then call someMethod(4*2) which is equivalent to someMethod(8). This will again enter the else block and call someMethod(4*8) which is equivalent to someMethod(32). Finally, it will hit the if block because 32 is greater than 10 and set the result to 32. Therefore, the output will be "someMethod(2) = 32".

Question 2

Which of the following code snippets returns the factorial of a given number? (Hint: Factorial of 5 = 5! = 1 * 2 * 3 * 4 * 5 = 120)

Accepted Answer

The correct implementation of factorial calculation is recursive in nature. It first checks if the given number is equal to 1, then returns 1 as the base case. For all other cases, it calls the factorial function recursively with the argument (num-1) and multiplies the result with the original number. Option D follows this logic and returns the correct result.

Question 3

What is the output of the following code snippet?
Public static int blackBox(int a) {
Int val;
If (a <= 0)
{
Val = 1;
}
Else
{
Val = a + blackBox(a - 2);
}
Return val;
}
Public static void main(String[] args)
{
System.out.println(blackBox(4));
}

Accepted Answer

When blackBox() is called with the argument 4, the else block is executed. The value of val is set to 4 + blackBox(2). When blackBox(2) is called, the else block is executed again and the value of val is set to 2 + blackBox(0). Finally, when blackBox(0) is called, the if block is executed and the value of val is set to 1. Now the program starts to evaluate the function calls that are waiting in the call stack. The value of blackBox(0) is returned to blackBox(2), and the value of blackBox(2) is returned to blackBox(4). Thus, the final value of val in blackBox(4) is 4 + 2 + 1 = 7, which is printed by the statement System.out.println(blackBox(4)).

Question 4

Given the method below, what is the output of the method call is div(10)?
Public static void div(int n)
{
If (n > 2)
{
Div(n % 3);
}
System.out.print(n / 3 + " ");
}

Accepted Answer

When the method is called with div(10), the condition (n > 2) is true so div(n%3) is called with argument div(10%3) which is div(1). Then the condition (n > 2) is false so the method prints (10 / 3) = 3 and returns to the previous call with argument n = 1. Now the method prints (1 / 3) = 0 and returns to the initial call with argument n = 10. Therefore, the output is "0 3".

Question 5

What is the output of the following code snippet?
Public static int fun(int x)
{
Int returnValue = 0;
If (x > 5)
{
ReturnValue = x;
}
Else
{
ReturnValue = fun(2 * x);
}
Return returnValue;
}
Public static void main(String[] args)
{
System.out.println("fun(2) = " + fun(2));
}

Accepted Answer

The function `fun` recursively calls itself with `2 * x` until `x` is greater than 5. Starting with `fun(2)`, it calls `fun(4)`, then `fun(8)`, which returns 8 since 8 > 5.

Question 6

What is the output of the following code snippet?
Public static int assignPriority(int priority)
{
Return priority + 2;
}
Public static void main(String[] args)
{
Int priority = assignPriority(3);
System.out.println("Priority: " + priority);
}

Accepted Answer

The method assignPriority takes an integer parameter 'priority' and returns the value of 'priority + 2'. In the main method, the assignPriority method is called with the argument 3, and the returned value is stored in the variable 'priority'. The value returned by the assignPriority method is 5, which is printed to the console along with the String "Priority:" using the System.out.println method. Therefore, the output of the program is "Priority: 5".

Question 7

Based on the code snippet below, which of the following statements is correct?
Public static void recursiveMethod(int count)
{
RecursiveMethod(count + 2);
System.out.println(count);
}
Public static void main(String[] args)
{
RecursiveMethod(1);
}

Accepted Answer

The recursiveMethod is called recursively with an increasing count value, but there is no base case to terminate the recursion. Hence, the code will infinitely recurse without ever reaching the System.out.println(count) statement. Therefore, no output will be produced. Additionally, there is a typo in the capitalization of the method name (should be recursiveMethod instead of RecursiveMethod).

Question 8

Which of the following is correct about a local variable?

Accepted Answer

A local variable is a variable that is declared within the scope of a method. It only exists within the method and is not visible to other methods. Therefore, option D is correct. Option A is incorrect because local variables are declared within the methods, not before all the methods. Option B is incorrect because local variables are not visible to other methods. Option C is incorrect because local variables can be declared in any method, not just the main method.

Question 9

For the given code snippet, which of the following statements is true?
Public static double raise(double rate)
{
Double newPayRate = rate * 1.1;
Return newPayRate;
}
Public static void main(String[] args)
{
Double rate = 40.0;
Double newPayRate = 0.0;
NewPayRate = raise(rate);
System.out.println("Pay rate: " + newPayRate);
}

Accepted Answer

The code defines a method named "raise" that takes a double parameter named "rate" and returns a double. It multiplies the rate by 1.1 and returns the result. 
The main method initializes the rate variable to 40.0, calls the raise method, which calculates a new pay rate of 44.0 (40.0 * 1.1). It then assigns the result to the newPayRate variable and prints "Pay rate: 44.0" to the console.

Question 10

Which method header is appropriate for this method body?
{
If (num1 < num2)
{
Return num1;
}
Return num2;
}

Accepted Answer

The method returns an integer value, so the method header should have a return type of "int".

Question 11

What is the output if the method call is testMyVal(6) in the following code snippet?
Public static void testMyVal(int nval)
{
If (nval > 0)
{
TestMyVal(nval - 2);
}
System.out.print(nval + " ");
}

Accepted Answer

The answer of What is the output if the method...

Question 12

Based on the code snippet, which of the following statements is correct?
Public static void reoccur(int count)
{
System.out.println(count);
Reoccur(count + 1);
}
Public static void main(String[] args)
{
Reoccur(1);
}

Accepted Answer

The code snippet executes and infinitely recurses, displaying 1, 2, 3, 4, and so on. The code calls the reoccur method, which takes the count variable as a parameter and prints out its value. It then calls the reoccur method again, passing in count + 1. This results in an infinite loop, as the method keeps calling itself with an incremented value of count.

Question 13

What is the output of the following code snippet?
Public static void main(String[] args)
{
Int gvar = 0;
Gvar = gvar + 10;
If (gvar > 0)
{
Int lvar = gvar + 1;
}
System.out.println(lvar);
}

Accepted Answer

The code will result in a compilation error at the line `System.out.println(lvar);` because `lvar` is declared inside the if statement and is not accessible outside of it. Therefore, it is out of scope and cannot be printed. Additionally, there is a syntax error where `Int` should be `int`, as Java is a case-sensitive language.

Question 14

Which of the following method declarations would be appropriate for a method that compares 2 numbers?
The method body is shown here:
{
Return num1 > num2;
}

Accepted Answer

Since the method returns a boolean value of whether num1 is greater than num2, the appropriate method declaration would be to have a return type of boolean. Option C has the correct declaration with the return type of boolean.

Quiz 5: Methods

What is the output of the following code snippet? Public static int someMethod(int x) { Int result = 0; If (x > 10) { Result = x; } Else { Result = someMethod(4 * x) ; } Return result; } Public static void main(String[] args) { System.out.println("someMethod(2) = " + someMethod(2) ) ; }

Which of the following code snippets returns the factorial of a given number? (Hint: Factorial of 5 = 5! = 1 * 2 * 3 * 4 * 5 = 120)

What is the output of the following code snippet? Public static int blackBox(int a) { Int val; If (a <= 0) { Val = 1; } Else { Val = a + blackBox(a - 2) ; } Return val; } Public static void main(String[] args) { System.out.println(blackBox(4) ) ; }

Given the method below, what is the output of the method call is div(10) ? Public static void div(int n) { If (n > 2) { Div(n % 3) ; } System.out.print(n / 3 + " ") ; }

What is the output of the following code snippet? Public static int fun(int x) { Int returnValue = 0; If (x > 5) { ReturnValue = x; } Else { ReturnValue = fun(2 * x) ; } Return returnValue; } Public static void main(String[] args) { System.out.println("fun(2) = " + fun(2) ) ; }

What is the output of the following code snippet? Public static int assignPriority(int priority) { Return priority + 2; } Public static void main(String[] args) { Int priority = assignPriority(3) ; System.out.println("Priority: " + priority) ; }

Based on the code snippet below, which of the following statements is correct? Public static void recursiveMethod(int count) { RecursiveMethod(count + 2) ; System.out.println(count) ; } Public static void main(String[] args) { RecursiveMethod(1) ; }

Which of the following is correct about a local variable?

Which method header is appropriate for this method body? { If (num1 < num2) { Return num1; } Return num2; }

What is the output if the method call is testMyVal(6) in the following code snippet? Public static void testMyVal(int nval) { If (nval > 0) { TestMyVal(nval - 2) ; } System.out.print(nval + " ") ; }

Based on the code snippet, which of the following statements is correct? Public static void reoccur(int count) { System.out.println(count) ; Reoccur(count + 1) ; } Public static void main(String[] args) { Reoccur(1) ; }

What is the output of the following code snippet? Public static void main(String[] args) { Int gvar = 0; Gvar = gvar + 10; If (gvar > 0) { Int lvar = gvar + 1; } System.out.println(lvar) ; }

Which of the following method declarations would be appropriate for a method that compares 2 numbers? The method body is shown here: { Return num1 > num2; }