Project

import java.util.*;
class MenuHandler
{
    static final Scanner Input=new Scanner(System.in);
    int displayMenu()
    {
        int choice;
        System.out.println("Welcome CGPA and SGPA calculater\n 1)Calculate SGPA and CGPA\n2)display SGPA of specific Semester\n 3)display CGPA \n 4) Exit");
        System.out.println("Enter Your Choice");
        choice=MenuHandler.Input.nextInt();
        return choice;
    }
    boolean isPositiveNumber(int n)
    {
        return n>0;
    }
}
class SGPACalculator extends MenuHandler
{
    int getGradePoints(int marks)
    {
        if (marks >= 90) return 10;
        else if (marks >= 80) return 9;
        else if (marks >= 70) return 8;
        else if (marks >= 60) return 7;
        else if (marks >= 50) return 6;
        else if (marks >= 40) return 5;
        else return 0;
    }
    double calculateSGPA(int numberOfSubjects)
    {
        int marks,credits;
        int totalGradePoints=0;
        int totalCredits=0;
        for(int i=1;i<=numberOfSubjects;i++)
        {
            do{
            System.out.println("Enter marks for Subject " + i + " (0-100):");
            marks=Input.nextInt();
            System.out.println("Enter Credits for Subject "+i);
            credits=Input.nextInt();
                if (marks>=0 && marks<=100 && isPositiveNumber(credits))
                    break;
                else
                    System.out.println("Invalid Marks or Credits. Please Enter Valid Marks or Credits");
            }while(true);
            int gradePoints=getGradePoints(marks);
            totalGradePoints+=gradePoints*credits;
            totalCredits+=credits;
        }
        double sgpa=(double)totalGradePoints/totalCredits;
        return sgpa;
    }
}
class CGPACalculator extends SGPACalculator
{
    double[] sgpa;
    double cgpa=0;
    void calculateCGPA(int numberOfSemester)
    {
        int NumberOfSubjects;
        double totalSgpa=0;
        sgpa=new double[numberOfSemester];
        for(int i=0;i<sgpa.length;i++)
        {
            do{
               System.out.println("Enter Number Of Subjects in "+(i+1)+" Semester");
               NumberOfSubjects=Input.nextInt();
                if(!isPositiveNumber(NumberOfSubjects))
                    System.out.println("Invalid Number.Please Enter Valid Number");
                else
                    break;
            }while(true);
               sgpa[i]=calculateSGPA(NumberOfSubjects);
               totalSgpa+=sgpa[i];
        }
        cgpa=totalSgpa/numberOfSemester;
    }
    void displayCGPA()
    {
        if(cgpa==0)
            System.out.println("Please Calculate CGPA first");
        else
        System.out.printf("Your CGPA is %.2f throughout the College\n",cgpa);
    }
    void displaySGPA()
    {
        if(sgpa==null || sgpa.length==0)
        {
            System.out.println("Please Calculate SGPA first");
            return;
        }
        do{
        System.out.println("Enter Semester Number(1 to "+sgpa.length+")");
        int Semester=Input.nextInt();
        if(isPositiveNumber(Semester) && Semester<=sgpa.length)
        {
            System.out.printf("SGPA=%.2f\n",sgpa[Semester-1]);
            break;
        }
        }while(true);
    }
}
class CGPA_SGPA_cal
{
    public static void main(String[] args)
    {
        CGPACalculator Calculator=new CGPACalculator();
        int NumberOfSemester;
        boolean flag1=true;
        do
        {
            switch(Calculator.displayMenu())
            {
                case 1:
                do{
                System.out.println("Enter Number of Semesters");
                NumberOfSemester=MenuHandler.Input.nextInt();
                    if(Calculator.isPositiveNumber(NumberOfSemester))
                        break;
                    else
                        System.out.println("Invalid Number.Please Enter Valid Number");
                }while(true);
                Calculator.calculateCGPA(NumberOfSemester);
                break;
                case 2:
                Calculator.displaySGPA();
                break;
                case 3:
                Calculator.displayCGPA();
                break;
                case 4:
                System.out.println("Exiting System");
                flag1=false;
                break;
                default :
                System.out.println("Invalid choice.Please Enter Valid choice");
            }
        }while(flag1);
        MenuHandler.Input.close();
    }
}