How to use this method in java? Using a method in java?

Not bad for a first stab at it, but you're guessing...not learning. A method definition can't be nested inside another method, so the whole thing, starting with "public static String letterGrade...", up to the "return percent;" needs to be moved outside of main(). You need to add a closing brace after the return statement to end the method body, too. You are using char values for letter grades, so the return type from letterGrade() should be char, not String. The Grade variable should be declared in your method as a local variable, and shouldn't be capitalized (Java convention is to capitalize class and interface names, not methods or variables.) Try adding "char grade;" to the front of your method. The percent argument should be an int or a double, not a string. You are comparing to int constants, so try int first. The percent argument is the input to your function. The calculated grade char is your output. The final statement should be "return grade;", not "return percent;"

Here you are. Hope this is what you're after. import java.util.*; // for scanner public class GradeList2 { public static void main(String[] args) { // partially by cbc // main method //tell the user the name of this program System.out.println ("This Program calculates grades for a class of students"); Scanner input = new Scanner(System.in); double class_average, bestPercent=0.0, lowPercent=101.0,sum=0.0; int Total_Points = 0, numStudents; int students, points, grade; int smallest = 0, largest = 0; // Prompt user to enter tge number of students System.out.println(" Enter number of students?"); numStudents = input.nextInt(); int[] student_points = new int [numStudents]; double[] percent =new double [numStudents]; char [] Grade = new char [numStudents]; // Prompt user to enter the total possible points in this semester System.out.println(" Enter the the total possible points"); Total_Points =input.nextInt(); // Prompt user to enter each students points System.out.println(" Now enter each students points"); for ( int i=0; i < numStudents; i++) { //ask the user to enter points for each student System.out.print(" Enter points for student " + (i+1)+" " ); student_points[i] = input.nextInt(); // check that the user total possible points are with in total possible points if ( Total_Points < student_points[i]){ System.out.print( "Sorry that is over the total possible, try again"); i--; } } for( int i=0; i< numStudents; i++) { // calculate and display percent and grade percent[i]= ((double) student_points[i] / Total_Points * 100); Grade[i] = LetterGrade(percent[i]); System.out.print(percent[i]+", "); System.out.println("Grade: "+Grade[i]); } for( int i=0; i< numStudents; i++) { // calculate the sum, the best and the lowest sum += percent[i]; //calculate best percent if (bestPercent < percent[i]) { bestPercent = percent[i]; } //calculate lowest percent if (lowPercent > percent[i]) { lowPercent = percent[i]; } } // calculate average class_average = sum / numStudents; System.out.println("Best percent: "+bestPercent); System.out.println("Lowest percent: "+lowPercent); System.out.println("Average percent: "+class_average); } // end of main public static char LetterGrade (double percent ) { char Grade; if (percent >= 90.0) {Grade='A';} else if (percent>= 80.0) {Grade='B';} else if (percent >= 70.0) {Grade='C';} else if (percent >= 60.0) {Grade = 'D';} else if (percent >= 50.0) {Grade = 'E' ;} else {Grade = 'F' ;} return Grade; } // end of LetterGrade } // end of class