[FIXED] #Help. Java code, getting the marks of 5 students and displaying the students who got A using Arrays method

Issue

I have a problem. I am tasked to write a Java program, using the array method, that receives the marks of 5 students, and then finds and displays the number of students getting A grade. The marks are (60,56,78,99,92.5). The criteria needed to get grade A is 80 marks and above.

Everything in my code went well, except for the last statement: System.out.println("The number of students "+count);

This is my code:

import javax.swing.JOptionPane;

public class Q2 {

 public static void main(String [] args) {

    double[] marks = new double[6];
    int numbers = 1;

    // This is for asking input
    for (int i = 0; i < marks.length; i++,numbers++) {
        String marksString = JOptionPane.showInputDialog (null,
                "Enter the marks for student "+numbers+": ");

        marks[i] = Double.parseDouble(marksString);

        int count = 0;
        if(marks[i] >= 80.0) {
            count++;
        }
    }
    System.out.println("The number of students "+count); 
 }

}

Everything in my code went well, except for the last statement: System.out.println("The number of students "+count);

I received an error:

Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - Erroneous tree type:

Is there anyone who can explain and correct my mistakes? :D

Solution

You wrongly declared count inside the for loop. As a result, it is not accessible outside the loop (hence the compilation error), and in addition, it's overwritten to 0 in each iteration of the loop, which means it will always have a value of 0 or 1 (before exiting the loop), instead of the correct count.

Move it outside the loop:

double[] marks = new double[6];
int numbers = 1;
int count = 0;
// This is for asking input
for (int i = 0; i < marks.length; i++,numbers++) {
  String marksString = JOptionPane.showInputDialog (null,
      "Enter the marks for student "+numbers+": ");
  marks[i] = Double.parseDouble(marksString);
  if(marks[i] >= 80.0) {
    count++;
  }
}
System.out.println("The number of students who got A is " + count); 

Answered By - Eran
Answer Checked By - Dawn Plyler (JavaFixing Volunteer)