Code in JAVA Displays for each GPA that exist in the student

Code in JAVA:

Displays for each GPA that exist in the students Database, the number of students with that GPA.

Solution

public static void main(String args[]) { Ranges ranges = new Ranges(\"Students\", 1); ranges.addRangeLengths(new Integer[]{40, 20, 20, 20}); int score; Scanner sc = new Scanner(System.in); while ((score = getScore(sc, \"Enter scores (or -1 to stop): \")) != -1) { ranges.addScore(score); } System.out.println(\"\ \" + ranges); } public static int getScore(Scanner sc, String message) { System.out.print(message); return (sc.hasNextInt()) ? sc.nextInt() : getScore(sc, \"Please insert number: \"); } import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class Ranges { private /*final*/ int startAt; private final String subject; private final List ranges = new ArrayList<>(); public Ranges(String subject, int startAt) { this.subject = subject; this.startAt = startAt; } public void addRangeLength(int length) { int min = (ranges.size() > 0) ? ranges.get(ranges.size() - 1).max + 1 : startAt; ranges.add(new Range(min, min + length - 1)); } public void addRangeLengths(Integer... lengths) { addRangeLengths(Arrays.asList(lengths)); } public void addRangeLengths(List lengths) { lengths.stream().forEach(length -> addRangeLength(length)); } public void addScore(int score) { for (Range range : ranges) { if (range.isInTheRange(score)) { range.increment(); break; } } } @Override public String toString() { StringBuilder sb = new StringBuilder(); ranges.stream().forEach(range -> sb.append(range).append(\"\ \") ); return sb.toString(); } private class Range { final int min; final int max; int count; Range(int min, int max) { this.min = min; this.max = max; } void increment() { count++; } boolean isInTheRange(int score) { return score >= min && score <= max; } @Override public String toString() { StringBuilder sb = new StringBuilder(); return sb.append(subject) .append(\" in the range of \") .append(min).append(\'-\').append(max).append(\": \") .append(count).toString(); } } }