Call stack behavior in Java - Interactive Code Practice

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Practice - 5 Tasks

1fill in blank

easy

Complete the code to call the method printMessage inside main.

Java

public class Test {
    public static void main(String[] args) {
        [1]();
    }
    public static void printMessage() {
        System.out.println("Hello from printMessage");
    }
}

🎯 Drag options to blanks, or click blank then click option

Amain

BprintMessage

CTest

DSystem.out.println

Attempts:

3 left

2fill in blank

medium

Complete the code to make methodB call methodC.

Java

public class StackExample {
    public static void methodA() {
        System.out.println("In methodA");
    }
    public static void methodB() {
        System.out.println("In methodB");
        [1]();
    }
    public static void methodC() {
        System.out.println("In methodC");
    }
    public static void main(String[] args) {
        methodA();
        methodB();
    }
}

🎯 Drag options to blanks, or click blank then click option

AmethodA

Bmain

CmethodC

DSystem.out.println

Attempts:

3 left

3fill in blank

hard

Fix the error in the recursive method countdown by completing the base case condition.

Java

public class Recursion {
    public static void countdown(int n) {
        if (n [1] 0) {
            System.out.println("Done!");
        } else {
            System.out.println(n);
            countdown(n - 1);
        }
    }
    public static void main(String[] args) {
        countdown(3);
    }
}

🎯 Drag options to blanks, or click blank then click option

A==

B>

C<=

D<

Attempts:

3 left

4fill in blank

hard

Fill both blanks to complete the base case and recursive step of the fibonacci method.

Java

public class Fib {
    public static int fib(int n) {
        if (n [1] 1) {
            return n;
        } else {
            return fib(n - 1) + fib(n - [2]);
        }
    }
    public static void main(String[] args) {
        System.out.println(fib(4));
    }
}

🎯 Drag options to blanks, or click blank then click option

A<=

B2

C==

D1

Attempts:

3 left

5fill in blank

hard

Fill all three blanks to complete the mutually recursive even/odd checker methods.

Java

public class EvenOdd {
    public static boolean isEven(int n) {
        if (n == 0) {
            return true;
        } else {
            return [1](n - 1);
        }
    }
    public static boolean isOdd(int n) {
        if (n [2] 0) {
            return false;
        } else {
            return [3](n - 1);
        }
    }
    public static void main(String[] args) {
        System.out.println(isEven(4));
        System.out.println(isOdd(3));
    }
}

🎯 Drag options to blanks, or click blank then click option

AisOdd

BisEven

C==

D>

Attempts:

3 left