Solution for question from https://carigold.com/portal/forums/showthread.php?t=681213

Marks.java

import java.util.Scanner;

/**
 * Solution for an exercise with the question:
 *
 * Write a program in Java called Marks, which prompts user for the number of marks, reads it from the keyboard, and
 * saves it in an int variable called numOfMarks. It then prompts user for the marks and saves them in an int array
 * called marks. Your program shall check that the marks value is between 0 and 100 and the number of marks is
 * between 1 to 30. The program should display number of marks that are more than 50. An example of output is shown
 * below:
 *
 *
 * Enter the number of marks: 2
 * Enter marks 1: 112
 * Invalid marks.. try again...
 * Enter marks 1: 49
 * Enter marks 2: 60
 * Number of marks more than 50 is 1
 */
public class Marks {
    private final Scanner scanner;

    /**
     * Constructor.
     */
    public Marks() {
        scanner = new Scanner(System.in);
    }

    /**
     * Call this method to run the program.
     */
    public void run() {
        int[] marks = promptNumOfMarks();

        for (int i = 0; i < marks.length; i++) {
            marks[i] = promptMark(i);
        }

        int moreThanFifty = countMoreThanFifty(marks);
        System.out.println("Number of marks more than 50 is " + moreThanFifty);
    }

    /**
     * Prompt for number of marks. Number of marks must be between 1 and 30.
     *
     * @return Array with the size of number of marks
     */
    private int[] promptNumOfMarks() {
        while (true) {
            System.out.print("Enter the number of marks: ");
            int numOfMarks = scanner.nextInt();

            if (numOfMarks >= 1 && numOfMarks <= 30) {
                return new int[numOfMarks];
            }

            System.out.println("Number of marks must be between 1 and 30.");
        }
    }

    /**
     * Prompt for mark given the index. Mark must be between 0 and 100.
     *
     * @param index The index of mark from the array
     * @return Mark
     */
    private int promptMark(int index) {
        int markPosition = index + 1;

        while (true) {
            System.out.print("Enter mark " + markPosition + ": ");
            int mark = scanner.nextInt();

            if (mark >= 0 && mark <= 100) {
                return mark;
            }

            System.out.println("Invalid marks. Try again.");
        }
    }

    /**
     * Count number of marks that are more than 50.
     *
     * @param marks Array of marks
     * @return Number of marks that are more than 50
     */
    private int countMoreThanFifty(int... marks) {
        int count = 0;

        for (int mark : marks) {
            if (mark > 50) {
                count++;
            }
        }

        return count;
    }


    /**
     * Program main entry.
     */
    public static void main(String[] args) {
        new Marks().run();
    }
}