Thread: have code - need one line fixed please!

hihi! here's my prompt and i think i did the program right but I can't get it to work

how do i fix this program?

this is the prompt btw: Create a S tudent class that stores the name, address, GPA, age, and major for a student. Additionally, the
S tudent class should implement the C omparable interface. Make the comparison of S tudent objects
based on the name, then the address, then the major, and finally the GPA. If the difference between two
objects when compared lies in the name, return a 1 or -1 depending on which object is lessor/greater.
If the difference in objects is in the address, return +/- 2. If the difference is in the major, return +/- 3. If the
difference is in the GPA, return +/- 4. Only return zero if all 4 fields are the same. This behavior deviates
slightly from the normal c ompareTo behavior (<0, 0, or >0), but we are ok with that for the purposes of
this lab.
Write a class called S tudentDriver to test your new method. Hard code several students into the main
method of the S tudentDriver class with small differences in different fields. That is, make one student
have one name and another a second name. Make a third student have the same name as the first, but a have
the third student have a different address, etc. Make sure your c ompareTo method finds each the
differences correctly.

the first is my comparable and the second is my driver
thanks!

public class Student implements Comparable {
String name;
String address;
String major;
double gpa;
 
public int compareTo(Object st) {
	Student s = (Student) st;
	if(this.name.compareTo(s.name) == 0) {
		if(this.address.compareTo(s.address) == 0) {
			if(this.major.compareTo(s.major) ==0) {
				if(this.gpa == s.gpa) {
					return 0; }
				else if(this.gpa < s.gpa) {
					return -4; }
				else {
					return 4; }}
			else {
				return 3 * this.major.compareTo(s.major); }}
		else {
			return 2 * this.address.compareTo(s.address); }}
	else {
		return this.name.compareTo(s.name);}
}}

 
public class StudentDriver{
 
    public static void main(String[] args) {
      Student st = new Student();
      Student Bob = new Student("Bob", "3 Bella Vista Court", "Phys", .8);
      Student Bob = new Student("Bob", "4 Bella Vista Court", "Chem", .9);
      Student Bob = new Student("Janice", "8 Bella Vista Court", "Eng", .7);
      Student Bob = new Student("Ian", "5 Bella Vista Court", "Math", .2);            
      }
 
}