% = ( Total Marks Obtained / Total Marks ) * 100

Write a program which calculates grade of a student on the basis of entered scores in all the given subjects:

If the average of total marks > 80, it would be treated as Grade ‘A’
If the average of total marks > 60 and < = 80, it would be treated as Grade ‘B’
If the average of total marks > 30 and < = 60, it would be treated as Grade ‘C’
If the average of total marks > 0 and < = 30, it would be treated as Grade ‘D’

We’ll be following two ways to achieve the same functionality.

• Without loop
• With loop

Example 1 . Java Program to Calculate and Print Grades of a Student

Program : 

public class StudentGrades {

    /**
     * A simple Java program to  find student grades
     * Assuming a student has 5 subjects
     **/
    public static void main(String[] args) {
        int totalSubjects = 5;   // assuming 5 subjects
        int maxMarksEachSub = 100;  // Each subject can have max 100 marks 
        double[] marks = new double[totalSubjects];
        double totalMarks = 0;
        double marksInPercentage;
        Scanner userInputObj = new Scanner(System.in);

        System.out.println("Please enter marks in all subjects.");
        for (int i = 0; i < marks.length; i++) {
            System.out.print("Subject " + (i + 1) + " : ");
            marks[i] = userInputObj.nextInt();

            /* Handling Invalid Input   */
            if (marks[i] > maxMarksEachSub || marks[i] < 0) {
                System.out.println("Invalid input " + marks[i] + "\nTerminating the program..... ");
                return;
            }
            totalMarks = totalMarks + marks[i];
        }
        marksInPercentage = (totalMarks / (totalSubjects * maxMarksEachSub)) * 100;

        System.out.println("Total marks obtained : " + totalMarks);
        System.out.println("Your Grade : " + getGrade(marksInPercentage));

    }

    private static String getGrade(double marksInPercentage) {
        if (marksInPercentage > 80 && marksInPercentage <= 100) {
            return "A";
        } else if (marksInPercentage > 60 && marksInPercentage <= 80) {
            return "B";
        } else if (marksInPercentage > 30 && marksInPercentage <= 60) {
            return "C";
        } else {
            return "D";
        }
    }
}

Output :  

Invalid Input : 

Example 2. Java Program to Calculate and Print Grades of a Student without loop

import java.util.Scanner;

public class StudentGrades {
    public static void main(String[] args) {
        Scanner ed = new Scanner(System.in);
        String name;
        int marks, javaScore, mathScore, webTechScore, cnScore, seScore;
        double avg;
        System.out.print("Enter name of Student = ");
        name = ed.next();
        System.out.println("Now, Number Out of 100 in following subject :- ");
        System.out.print("Java : ");
        javaScore = ed.nextInt();
        System.out.print("Maths : ");
        mathScore = ed.nextInt();
        System.out.print("Web Technologies : ");
        webTechScore = ed.nextInt();
        System.out.print("Computer Network : ");
        cnScore = ed.nextInt();
        System.out.print("Software Engineering : ");
        seScore = ed.nextInt();
        marks = javaScore + mathScore + cnScore + seScore + webTechScore;
        avg = ((double) marks) / 500;
        System.out.println("Name = " + name);
        System.out.println("total marks " + marks);
        if (avg > 0.8 && avg <= 1) {
            System.out.println("Grade = A");
        } else if (avg > 0.6 && avg <= 0.8) {
            System.out.println("Grade = B");
        } else if (avg > 0.3 && avg <= 0.6) {
            System.out.println("Grade = C");
        } else if (avg >= 0 && avg <= 0.3) {
            System.out.println("Grade = D");
        } 
    }
}

Output:

Example 3 . Java Program to Calculate and Print Grades of a Student using for loop

Program:

import java.util.Scanner;

public class StudentGrades {
    public static void main(String[] args) {
        Scanner ed = new Scanner(System.in);
        String name;
        int marks = 0, subjectCount;
        double avg;
        System.out.print("Enter name of Student = ");
        name = ed.next();
        System.out.print("Enter Number of Subjects = ");
        subjectCount = ed.nextInt();
        System.out.println("Now, Number Out of 100 in following subject :- ");
        for (int i = 0; i < subjectCount; i++) {
            marks += ed.nextInt();
        }
        avg = ((double) marks) / subjectCount;
        System.out.println("Name = " + name);
        System.out.println("total marks " + marks);
        if (avg > 80 && avg <= 100) {
            System.out.println("Grade = A");
        } else if (avg > 60 && avg <= 80) {
            System.out.println("Grade = B");
        } else if (avg > 30 && avg <= 60) {
            System.out.println("Grade = C");
        } else if (avg >= 0 && avg <= 30) {
            System.out.println("Grade = D");
        }
    }
}

Output:

Enter name of Student = ProgrammerBay
Enter Number of Subjects = 5
Now, Number Out of 100 in following subject :- 
83
65
81
67
72
Name = ProgrammerBay
total marks 368
Grade = B