Using array of char from another method to count occurances - char can't be converted to char[] -

Question

Please be kind as I am very new to Java (and programming in general).

I am trying to write a method that will count the occurrences of grades, and I think I have it figured out, but I am losing my mind trying to test it (i TestingPage) I get the error 'char can't be converted to char[]' The method with the grades (getGrades), converted int to char based on the level of grades (marks).

Im sure the solution is simple, but I just can't seem to figure out what I am doing wrong, or what I need to include or take out to test it.

public class ProcessMarks {
    Marks testMarks = new Marks(); 
    int[] marks = testMarks.getMarks();

    //Method to create a new array of grades based on marks array
    public static char getGrades(int marks[]){
        int a = 90;
        int b = 75;
        int c = 60;
        int d = 50;
        int e = 45;
        char[] grades = new char [marks.length];
        char gradedMarks = grades[0]
        //else is F for fail! 
        for (int i = 0; i < marks.length; i++){
            if (marks[i] >= a)
                grades[i] = 'A';
            else if (marks[i] >= b && marks[i] < a)
                grades[i] = 'B';
            else if (marks[i] >= c && marks[i] < b)
                grades[i] = 'C';
            else if (marks[i] >= d && marks[i] < c)
                grades[i] = 'D';
            else if (marks[i] >= e && marks[i] < d)
                grades[i] = 'B';
            else 
                grades[i] = 'F';
        }
        for (int n = 0; n < grades.length; n++) {
            System.out.print(grades[n] + " ");
            if (n % 10 == 9)
                System.out.println();
        }

            return gradedMarks;
              
            }
    
    //Method to establish total occurrences of each grade
    public static char gradesDistn (char getGrades[]){
      char[] grades = getGrades;
      char gradesDistn = 0;

         int a = 0;
         int b = 0;
         int c = 0;
         int d = 0;
         int e = 0;
         int f = 0;

         for (int i = 0; i < grades.length; i++){
             if (grades[i] == 'A')
                 a++;
             else if (grades[i] == 'B')
                 b++;
             else if (grades[i] == 'C')
                 c++;
             else if (grades[i] == 'C')
                 c++;
             else if (grades[i] == 'D')
                 d++;
             else if (grades[i] == 'E')
                 e++;
             else
                 f++;
         }
         System.out.println("A: " + a);
         System.out.println("B: " + b);
         System.out.println("C: " + c);
         System.out.println("D: " + d);
         System.out.println("E: " + e);
         System.out.println("F: " + f);
         
         return gradesDistn;
         }
     }


public class TestingPage {
    public static void main(String[] args) {
        int[] marks = Marks.getMarks(); 
        char[] grade = ProcessMarks.getGrades(marks); // char cannot be converted to char[] 
        
      
        int median = ProcessMarks.getMedian(marks);
        int min = ProcessMarks.getMin(marks);
        int range = ProcessMarks.getRange(marks);
        int mean = ProcessMarks.getMean(marks);
        int mode = ProcessMarks.getMode(marks);
        char grades = ProcessMarks.getGrades(marks);
        int distribution = ProcessMarks.gradesDistn(grade);
        
        System.out.println(range);
        
       
           }
     
}

Answer 1

In your TestingPage class void main method you are doing this:

char[] grade = ProcessMarks.getGrades(marks);

This means you are expecting a char[] in return but the method getGrades returns only a char as below:

public static char getGrades(int marks[]) { }

What data-type a method will return you need to catch the response in the exact same data-type.

If you do the below, your error [ char cannot be converted to char[] ] goes:

char grade = ProcessMarks.getGrades(marks); 

But I can see many other flaws as well in your methods.

Example: Like the getGrades() returns gradedMarks which is never populated except the declaration point. It will always return the same value.

Answer 2

In your main method:

char[] grade = ProcessMarks.getGrades(marks); 

getGrades() returns char , but you assign it to the array of chars char[] , which is not compatible and cannot even be implicitly casted.

Generally, remember, that type T and type T[] are completely different types.

Answer 3

Jandie, as discussed offline - you need to define the type as an array. The above answers should be accepted as they are spot on.

public static char getGrades(int marks[]){

becomes

public static char[] getGrades(int marks[]){