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AP US Government

AP Computer Science A - 2.5 Calling a Non-Void Method

AP Computer Science A - 5.1 Anatomy of a Class

AP Computer Science A - 5.2 Constructors

AP Computer Science A - 5.4 Accessor Methods

AP Computer Science A - 5.6 Writing Methods

AP Computer Science A - Unit 5 Overview: Writing Classes

Consider the following method: public void printFibonacci(int n) { int a = 0; int b = 1; System.out.print(a + " " + b + " "); for (int i = 2; i < n; i++) { int sum = a + b; System.out.print(sum + " "); a = b; b = sum; } } Assume that the method printFibonacci(6) appears in a method in the same class. What is printed as a result of the method call?

Consider the following method: public void printEvenNumbers(int n) { for (int i = 2; i <= n; i += 2) { System.out.print(i + " "); } } Assume that the method printEvenNumbers(8) appears in a method in the same class. What is printed as a result of the method call?

Consider the following method: public void printPowersOfTwo(int n) { for (int i = 0; i <= n; i++) { int power = (int) Math.pow(2, i); System.out.print(power + " "); } } Assume that the method printPowersOfTwo(5) appears in a method in the same class. What is printed as a result of the method call?

Consider the following method: public void printReverse(String str) { for (int i = str.length() - 1; i >= 0; i--) { System.out.print(str.charAt(i)); } } Assume that the method printReverse("Hello") appears in a method in the same class. What is printed as a result of the method call?

Consider the following method: public void printVowels(String str) { str = str.toLowerCase(); for (int i = 0; i < str.length(); i++) { char ch = str.charAt(i); if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') { System.out.print(ch + " "); } } } Assume that the method printVowels("OpenAI") appears in a method in the same class. What is printed as a result of the method call?

Consider the following method: public void printFactors(int n) { for (int i = 1; i <= n; i++) { if (n % i == 0) { System.out.print(i + " "); } } } Assume that the method printFactors(24) appears in a method in the same class. What is printed as a result of the method call?

Consider the following method: public void printPrimeNumbers(int n) { for (int i = 2; i <= n; i++) { boolean isPrime = true; for (int j = 2; j <= Math.sqrt(i); j++) { if (i % j == 0) { isPrime = false; break; } } if (isPrime) { System.out.print(i + " "); } } } Assume that the method printPrimeNumbers(20) appears in a method in the same class. What is printed as a result of the method call?

Consider the following method: public void calculateSquareRoot(double n) { double squareRoot = Math.sqrt(n); printSquareRoot(n, squareRoot); } public void printSquareRoot(double n, double squareRoot) { System.out.print("Square root of " + n + " = " + squareRoot); } Assume that the method calculateSquareRoot(16) appears in a method in the same class. What is printed as a result of the method call?

Consider the following method. public boolean isValidEmail(String email) { /* implementation not shown */ } Which of the following lines of code, if located in a method in the same class as isValidEmail, will compile without an error?

What happens when we try to run the following? class D { public D(int x) { } } class E extends D { public E() { } } public class C { public static void main(String[] args) { E e = new E(); } }

What happens when we try to run the following? class J { public J(String x) { } } class K { public K() { } } public class L { public static void main(String[] args) { K k = new K(); } }

Given the block of code below, answer the following question: ```java class Animal { // constructor not shown } class Dog extends Animal { // constructor not shown public void makeSound() { System.out.println("Woof! Woof!"); } } ``` Question: Consider the code above. If we create an object of the `Dog` class and call the `makeSound()` method on that object, what will be outputted?

How can we fix the following class so it compiles? public class Weather { private int currentTemp; public Weather(int temp) { currentTemp = temp; } public void resetTemp() { currentTemp = newTemp; } }

Why does the following class does not compile? public class Weather { private int currentTemp; public Weather(int temp) { currentTemp = temp; } public void resetTemp(double newTemp) { currentTemp = newTemp; } }

In the following code block, what is the scope of the variable "name"? public void printGreeting(String name) { System.out.println("Hi " + name); }

What output do we get if we run the following code? class X { private int a; private int y; public X() { this.a = 5; } public X(int y) { this(); this.y = y; System.out.print(a); System.out.print(this.y); } } public class Z { public static void main(String[] args) { X x = new X(3); } }

Does the following code compile successfully? ```java class X { private int a; private int y; public X() { this.a = 10; } public X(int y) { this(); this.y = y * 10; System.out.print(this.a + " "); System.out.print(this.y + " "); } } public class Z { public static void main(String[] args) { X x = new X(5); } } ```

What is the output of the following code? ```java class X { private int a; private int y; public X() { a = 15; } public X(int y) { this(); X.y = y; System.out.print(this.a + " "); System.out.print(this.y + " "); } } public class Z { public static void main(String[] args) { X x = new X(5); } } ```

What output do we get if we run the following code? ```java class X { private int a; private int y; public X() { this.a = 3; } public X(int y) { this("z"); this.y = y; System.out.print(this.a + " "); System.out.print(this.y + " "); } } public class Z { public static void main(String[] args) { X x = new X(7); } } ```