Question

Convert this code written in Python to Java:

students = int(input("How many students are in your class?" ))

while students<0:

    print("Invalid # of students, try again.")

    students = int(input("How many students are in your class?" ))

tests = int(input("How many tests in this class? "))

while tests<0:

    print("Invalid # of tests, try again.")

    tests = int(input("How many tests in this class? "))

print("Here we go!")

# Here we are creating a list called class_average to store average of all students.

class_average = []

for i in range(1, students+1):

    # Here we are creating a list called student_marks to store the marks of the student.

    student_marks = []

    print("**** Student #",i, "****")

    for j in range(1,tests+1):

        marks = int(input("Enter score for test #{}: ".format(j)))

        while marks<0:

            print("Invalid score, try again")

            marks = int(input("Enter score for test #{}: ".format(j)))

        # If marks is valid then we are adding it to student_marks list.

        student_marks.append(marks)

    # Here we are finding average of student marks and storing in student_average variable.

    student_average = sum(student_marks) / len(student_marks)

    # Here we are rounding of average to get perfect decimal

    rounded_average = round(student_average, 3)

    print("Average score for student #", i, "is ", rounded_average)

    # After finding student average, we are adding it to class_average list.

    class_average.append(rounded_average)

# Here we are calculating whole class average and storing in variable whole_class_average

whole_class_average = sum(class_average) / len(class_average)

# Here we are rounding off result to get it prefect decimal

rounded_class_average = round(whole_class_average, 2)

print("Average score for all students is: ", rounded_class_average)

Answer 1

JAVA Program:

import java.io.*;
import java.util.*;

public class Main
{
   public static void main(String[] args) {
       int students,tests;
       double marks;
       Scanner sc = new Scanner(System.in);
       System.out.print("How many students are in your class?");
       students = sc.nextInt();
       while(students<0){
       System.out.println("Invalid # of students, try again.");
       System.out.print("How many students are in your class?");
       students = sc.nextInt();
       }
       System.out.print("How many tests in this class? ");
       tests = sc.nextInt();
       while(tests<0){
       System.out.println("Invalid # of tests, try again.");
       System.out.print("How many tests in this class? ");
       tests = sc.nextInt();
       }
       System.out.println("Here we go!");
       //Here we are creating a list called class_average to store average of all students.
       ArrayList <Double> class_average = new ArrayList<Double>();
       for(int i=1;i<=students;i++){
       //Here we are creating a list called student_marks to store the marks of the student.
       ArrayList <Double> student_marks = new ArrayList<Double>();
       System.out.println("**** Student #"+i+"****");
       for(int j=1;j<=tests;j++){
       System.out.print("Enter score for test #"+j+": ");
       marks = sc.nextDouble();
       while(marks<0){
       System.out.println("Invalid score, try again");
       System.out.print("Enter score for test #"+j+": ");
       marks = sc.nextDouble();
       }
       student_marks.add(marks);
       }
       double student_average=0;
       for(int j = 0; j< student_marks.size(); j++)
student_average += student_marks.get(j);
student_average /= student_marks.size();
System.out.printf("Average score for student # %d is %.3f\n",i,student_average);
class_average.add(student_average);
       }
       double whole_class_average=0;
       for(int j = 0; j< class_average.size(); j++)
whole_class_average += class_average.get(j);
whole_class_average /= class_average.size();
System.out.printf("Average score for all students is: %.2f",whole_class_average);
   }
}

Output: