public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;
}

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){

  }
}

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){
    age = age + 1;
  }
}

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){
    this.age = this.age + 1;
  }
}

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){
    this.age = this.age + 1;
  }
}

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){
    this.age = this.age + 1;
  }

  void grade(int credits, int grade_points){

  }
}

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){
    this.age = this.age + 1;
  }

  void grade(int credits, int grade_points){
    int current_points = this.gpa * this.credits;
  }
}

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){
    this.age = this.age + 1;
  }

  void grade(int credits, int grade_points){
    int current_points = (int)this.gpa * this.credits;
  }
}

import java.lang.Math;

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){
    this.age = this.age + 1;
  }

  void grade(int credits, int grade_points){
    int current_points = (int)Math.round(this.gpa
                                    * this.credits);
  }
}

import java.lang.Math;

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){
    this.age = this.age + 1;
  }

  void grade(int credits, int grade_points){
    int current_points = (int)Math.round(this.gpa
                                    * this.credits);
    this.credits += credits;
    current_points += grade_points;
  }
}

import java.lang.Math;

public class Student{
  String name = "name";
  int age = 19;
  String student_id = "123456987";
  int credits = 0;
  double gpa = 0.0;

  void birthday(){
    this.age = this.age + 1;
  }

  void grade(int credits, int grade_points){
    int current_points = (int)Math.round(this.gpa
                                    * this.credits);
    this.credits += credits;
    current_points += grade_points;
    this.gpa = (double)current_points / this.credits;
  }
}