Question

Part A

Write a Java program that reads an integer n from the keyboard and loops until −13 ≤ n ≤ 13 is successfully entered. A do-while loop is advised.

Part B

Write a Java program that reads an integer n from the keyboard and prints the corresponding value n!. [This is n factorial]. You must verify that the input integer satisfies the constraint 0 ≤ n ≤ 13; keep looping until the constraint is satisfied.  

Will give thumbs up to best answer.

Answer 1

a)
import java.util.Scanner;

public class KeepReadingUntilValid {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n;
        do {
            n = in.nextInt();
        } while (n < -13 || n > 13);
    }

}


b)
import java.util.Scanner;

public class FactorialOfValid {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n;
        do {
            n = in.nextInt();
        } while (n < 0 || n > 13);

        int f = 1;
        for(int i = 1; i <= n; ++i) {
            f *= i;
        }
        System.out.println(f);
    }

}