Scanner reader = new Scanner(System.in);
        System.out.println("Welcome to the Exam Histogram program by Henry Yates.");
        System.out.println("Please enter 0-100 for the marks and enter -1 to complete data entry");
        int total = 0, count = 0;
        double average = 0.0;
        int marks = 0;
        int BotMarks = 0;
        int LowMarks = 0;
        int MedMarks = 0;
        int HighMarks = 0;
        int Highest = 0;
        int Lowest = 1000;
        int MarksEntered = 0;
        while (marks != -1) {
            try {
                marks = reader.nextInt();
            } catch (InputMismatchException e) {
                marks = 1000;
                continue;
            }
            while (marks < -1 || marks > 100) {
                if (marks == -1) {
                    total++;
                    count=count-1;
                } else {
                    System.out.println("Invalid input please enter 0-100");
                    marks = reader.nextInt();
                }

            }
            total = total + marks;
            count++;
            //total++;


            if (marks > Highest) {
                Highest = marks;
            }
            if (marks < Lowest && marks >= 0) {
                Lowest = marks;
            }
            if (marks != -1) {
                MarksEntered++;
            }
            if (marks <= 100 && marks >= 70) {
                HighMarks++;
            } else if (marks <= 69 && marks >= 40) {
                MedMarks++;
            } else if (marks <= 39 && marks >= 30) {
                LowMarks++;
            } else if (marks >= 29 || marks == 0 || marks >= 1) {
                BotMarks++;
            }

        } // end of main while loop
        System.out.print("70-100: ");
        for (int a = 0; a < HighMarks; a++) {
            System.out.print("*");
        }
        System.out.println("");
        System.out.print("40-69 : ");
        for (int a = 0; a < MedMarks; a++) {
            System.out.print("*");
        }
        System.out.println("");
        System.out.print("30-39 : ");
        for (int a = 0; a < LowMarks; a++) {
            System.out.print("*");
        }
        System.out.println(" ");
        System.out.print("0-29  : ");
        for (int a = 0; a < BotMarks; a++) {
            System.out.print("*");
        }
        System.out.println("");
        int StudentsPass = 0;
        count=count-1;
        total++;
        average = (total / count);
        StudentsPass = MedMarks + HighMarks;
        System.out.println("The amount of students who passed are " + StudentsPass);
        System.out.println("The Lowest Mark is: " + Lowest);
        System.out.println("The Highest Mark is: " + Highest);
        System.out.println("The Average Mark is: " + average);

    }
}