Homework on solving problem using Java

import java.util.Scanner;


public class PermutationCombinationCalculator {


public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);


while (true) {
System.out.println("Would you like to perform a permutation or
combination? Enter 'P' for permutation or 'C' for combination:");
String choice = scanner.next().toUpperCase();


if (choice.equals("P")) {
calculatePermutation(scanner);
break;
} else if (choice.equals("C")) {
calculateCombination(scanner);
break;
} else {
System.out.println("Invalid input. Please enter 'P' for permutation or 'C'
for combination.");
}
}


scanner.close();
}


public static void calculatePermutation(Scanner scanner) {
System.out.println("Enter the value of n:");
int n = scanner.nextInt();