Java Program to Find Grade from Marks

You can find grade from marks in Java using if-else statements like if (marks >= 90) grade = 'A'; else if (marks >= 80) grade = 'B'; and so on, to assign grades based on score ranges.

Examples

Inputmarks = 95

OutputGrade: A

Inputmarks = 72

OutputGrade: C

Inputmarks = 40

OutputGrade: F

How to Think About It

To find the grade from marks, first understand the score ranges for each grade. Then check the marks against these ranges using if and else if conditions from highest to lowest. Assign the grade when the marks fit a range.

Algorithm

1

Get the marks as input.

2

Check if marks are 90 or above, assign grade 'A'.

3

Else if marks are 80 or above, assign grade 'B'.

4

Else if marks are 70 or above, assign grade 'C'.

5

Else if marks are 60 or above, assign grade 'D'.

6

Else assign grade 'F'.

7

Print the grade.

Code

java

import java.util.Scanner;

public class GradeFinder {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter marks: ");
        int marks = sc.nextInt();
        char grade;

        if (marks >= 90) grade = 'A';
        else if (marks >= 80) grade = 'B';
        else if (marks >= 70) grade = 'C';
        else if (marks >= 60) grade = 'D';
        else grade = 'F';

        System.out.println("Grade: " + grade);
        sc.close();
    }
}

Output

Enter marks: 85
Grade: B

Dry Run

Let's trace marks = 85 through the code

1

Input marks

marks = 85

2

Check if marks >= 90

85 >= 90 is false, move to next condition

3

Check if marks >= 80

85 >= 80 is true, assign grade = 'B'

4

Print grade

Output: Grade: B

Condition	Result	Grade Assigned
marks >= 90	false	none
marks >= 80	true	B

Why This Works

Step 1: Check highest grade first

We start with if (marks >= 90) to assign grade 'A' because higher marks get higher grades.

Step 2: Use else if for next ranges

Each else if checks the next lower range, so only one grade is assigned.

Step 3: Assign default grade

If none of the above conditions match, grade 'F' is assigned as the default for failing marks.

Alternative Approaches

Using switch with ranges (Java 14+)

java

import java.util.Scanner;

public class GradeFinderSwitch {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter marks: ");
        int marks = sc.nextInt();
        char grade;

        switch (marks / 10) {
            case 10:
            case 9: grade = 'A'; break;
            case 8: grade = 'B'; break;
            case 7: grade = 'C'; break;
            case 6: grade = 'D'; break;
            default: grade = 'F';
        }

        System.out.println("Grade: " + grade);
        sc.close();
    }
}

This uses integer division and switch-case for cleaner code but only works well for marks 0-100.

Using ternary operator

java

import java.util.Scanner;

public class GradeFinderTernary {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter marks: ");
        int marks = sc.nextInt();

        char grade = (marks >= 90) ? 'A' :
                     (marks >= 80) ? 'B' :
                     (marks >= 70) ? 'C' :
                     (marks >= 60) ? 'D' : 'F';

        System.out.println("Grade: " + grade);
        sc.close();
    }
}

This approach is concise but can be harder to read for beginners.

Complexity: O(1) time, O(1) space

Time Complexity

The program uses simple if-else checks without loops, so it runs in constant time regardless of input.

Space Complexity

Only a few variables are used, so space usage is constant.

Which Approach is Fastest?

All approaches run in constant time; switch-case may be slightly faster but less flexible.

Approach	Time	Space	Best For
If-Else	O(1)	O(1)	Clear and easy to understand
Switch-Case	O(1)	O(1)	Cleaner code for fixed ranges
Ternary Operator	O(1)	O(1)	Concise code, less readable