Why is this Java code not working calculate average max and min? -

i supposed build program gets grades in class , calculates min , max , average ask if want continue. code used it's still not working. can see mistake is?

public class calculateavgmaxmin {     public static void main(string[] args)     {         scanner input = new scanner(system.in); // declares scanner input         linkedlist<integer> list = new linkedlist<integer>(); // declare new linkedlist of variables grades          int answer = 1; // declare variable answer =1          { // start of loop               system.out.print("please enter name of course:"); // gives prompt enter name of course              // goes next line              string course=input.nextline(); // declare course string , sets value input              system.out.println("please enter scores " + course + " on single line , type -1 @ end"); //prompts user enter scores class in 1 line , -1 stop              int max=-100; // declare max integer = -100             int min=500;//declare min integer = 500              int sum=0;// declare sum intgetr = 0             int grade;     // declare grade integer                grade=input.nextint(); // set grade next user iput              if (grade==-1) //  if statement if sentinel value set stop                 break;              list.add(grade); // adds grade grade variable linkedlist             sum=sum+grade;// put value of sum sum , new grade              if (grade>max) // if statement if grade more max sets max grade                 max=grade;             if (grade<min) // if statement if grade less min sets min grade                 min=grade;              system.out.println("the course name: "+ course); // prints message of course name entered             system.out.println("number of scores :"+list.size()); // sits number of scores using size of list             system.out.printf("the average score: %.2f" ,(double)sum/list.size()); // calculates average 2 decimal values using sum divided length of list             system.out.println(); // goes next line             system.out.println("the minimum score: "+min); // sets minimum value min             system.out.println("the maximum score :"+max);// sets minimum value min             answer = joptionpane.showconfirmdialog(null," continue?"); // sets value of variable answer confrim dialog box         } while (answer == 0);  // sets condition loop answer == o continue if yes selected      } } 

i think following lines incorrect:

int max=-100; // declare max integer = -100  int min=500;//declare min integer = 500 

they should be:

int max= 500; // declare max integer = -100  int min=-100;//declare min integer = 500 

also should moved outside do-while.