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74 lines
2.0 KiB
74 lines
2.0 KiB
3 months ago
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## Factorial Master
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### Instructions
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Create an abstract class `Factorial` that will serve as the base class for calculating the factorial of a number. This class should have an abstract method `calculate` that will be implemented by its child classes.
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Implement two child classes:
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- `IterativeFactorial` which implements the factorial calculation using an iterative approach.
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- `RecursiveFactorial` which implements the factorial calculation using a recursive approach.
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> Note: The factorial of 0 is 1, according to the [convention](https://www.chilimath.com/lessons/intermediate-algebra/zero-factorial/)
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#### Formula for factorial calculation:
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n! = n × (n−1) × (n−2) × … × 1
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And an example:
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5! = 5 × 4 × 3 × 2 × 1 = 120
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### Expected Abstract Class
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```java
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public abstract class Factorial {
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public abstract long calculate(int n);
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}
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public class IterativeFactorial extends Factorial {
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@Override
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public long calculate(int n) {
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// iterative factorial calculation
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}
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}
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public class RecursiveFactorial extends Factorial {
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@Override
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public long calculate(int n) {
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// recursive factorial calculation
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}
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}
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```
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### Usage
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Here is a possible ExerciseRunner.java to test your classes:
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```java
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public class ExerciseRunner {
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public static void main(String[] args) {
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Factorial iterativeFactorial = new IterativeFactorial();
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Factorial recursiveFactorial = new RecursiveFactorial();
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// Test iterative factorial
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int number = 5;
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long iterativeResult = iterativeFactorial.calculate(number);
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System.out.println("Iterative Factorial of " + number + " is: " + iterativeResult); // Expected output: 120
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// Test recursive factorial
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long recursiveResult = recursiveFactorial.calculate(number);
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System.out.println("Recursive Factorial of " + number + " is: " + recursiveResult); // Expected output: 120
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}
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}
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```
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### Expected Output
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```shell
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$ javac *.java -d build
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$ java -cp build ExerciseRunner
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Iterative Factorial of 5 is: 120
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Recursive Factorial of 5 is: 120
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$
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```
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