PD4NamithGStudentArrayTester.java

/*****************************************************************************************************************
NAME: Namith Gangireddyvari     
PERIOD: 4
DUE DATE: 1/30/22

PURPOSE: Review how to declare and initialize arrays of references. Review the sequential search algorithm.

WHAT I LEARNED: That if you close a scanner that uses System.in, it will prevent the program 
from using System.in again 
         
CREDITS (BE SPECIFIC: FRIENDS, PEERS, ONLINE WEBSITE): 

****************************************************************************************************************/
import java.util.Scanner;

public class PD4NamithGStudentArrayTester{
  public static void main (String [] args){
    StudentBody students = new StudentBody();
    students.init();

    Scanner keyboard = new Scanner (System.in);
    System.out.println("Enter the id of the student you are looking for: "); 
    int studentID = keyboard.nextInt();

    Student	target =students.search(studentID); 

    if(target != null)
    System.out.println(target); else
    System.out.println ("Student not found ...");

    System.out.println("Student Body Information:\n" + students);

    Student[] honorsStudents = students.aboveAvgStudents();

    System.out.println("The honors students are "); 
    for (Student s: honorsStudents){
      System.out.println (s);              
    }

  }
} // StudentArrayTester


class StudentBody {
	private Student[] students;
	
	public StudentBody() {
    students = new Student[3];
    students[0] = new Student(); 
    students[1] = new Student();
    students[2] = new Student();
	}

  //Prompts user to enter data
	public void init() {
    Scanner sc = new Scanner(System.in);
    for(int i = 0; i < students.length; i++){
      System.out.print("\n Enter Student " +(i+1)+ "s' Name: ");
      String name = sc.next();
      System.out.print("\n Enter ID: ");
      int id = sc.nextInt();
      System.out.print("\n Enter gPA: ");
      double grade = sc.nextDouble();
      students[i] = new Student(name, id, grade);
    }
	}
	
	//returns null if Student with ID “id” is not found in students
	public Student search(int id) {
    for (int i = 0; i < students.length; i++){
      if(id == students[i].getStudentID()){
        return students[i];
      }
    }
    return null;
	}

	//returns a double representing the average GPA of all students in the Student Body
	public double calcAvgGPA() {
    double avg = 0;
    for (int i = 0; i < students.length; i++){
      avg+= students[i].getGPA();
    }
    return avg/students.length;
	}

	/* returns an array of Students that contain first students in StudentBody 
   whose GPA is greater than the average GPA of the student body you must call the calcAvgGPA 
   method in this method to get credit
	*/
	public Student[] aboveAvgStudents() {
    int count = 0;
    for (int i = 0; i < students.length; i++){
      if(students[i].getGPA() >= calcAvgGPA()){
        count++;
      }
    }

    Student[] abvAvgStu = new Student[count];
    count = 0;
    for (int i = 0; i < students.length; i++){
      if(students[i].getGPA() >= calcAvgGPA()){
        abvAvgStu[count] = students[i];
      }
    }
    return abvAvgStu;
	}
	
	public String toString() {
    String print = "";
    for(int i = 0; i < students.length; i++){
      print += students[i].toString();
    }
    return print;
	}
}

class Student{
   private String name;
   private int studentID;
   private double gPA;
   
   /* precondition: none
postcondition: create a Student object with default instance variable values */
   public Student()
  {
      name = "unknown";
      studentID = 0;
      gPA = 0.0;
   }
   
 /* precondition: method must be called with String representing name, int representing student ID,      
 and double from 0.0-5.0 representing GPA
postcondition: create a Student object with specified instance variable values */
   public Student(String iName, int iStudentID, double iGPA){
      name = iName;
      studentID = iStudentID;
      gPA = iGPA;
   }
   
 /* precondition: must be called with valid Student object
postcondition: returns the name, student ID, and GPA of a student in the form of a string */
   public String toString(){
      return "Name: "+name+"\tStudent ID: "+studentID+"\tGPA: "+gPA;
   }

 /* precondition: must be called with valid Student object, must be called with a double argument from 0.0-5.0
postcondition: reassign the value of the argument to a Student’s GPA*/ 
   public void setGPA(double nGPA){
      gPA=nGPA;
   }
   
 /* precondition: must be called with valid Student object
postcondition: return the name of the Student */ 
   public String getName(){
      return name;
   }
   
 /* precondition: must be called with valid Student object
postcondition: will return the ID of the Student*/ 
   public int getStudentID(){
      return studentID;
   }
   
 /* precondition: must be called with valid Student object
postcondition: will return the GPA of the Student*/ 
   public double getGPA(){
      return gPA;
   }

}//end Student class

/*
Output:
Enter Student 1s' Name: Joe
Enter ID: 1578840
Enter gPA: 4.0
Enter Student 2s' Name: Bob
Enter ID: 157367
Enter gPA: 3.5
Enter Student 3s' Name: Cam
Enter ID: 139581
Enter gPA: 4.0
Enter the id of the student you are looking for: 
139581
Name: Cam	Student ID: 139581	GPA: 4.0
Student Body Information:Name: Joe	Student ID: 1578840	GPA: 4.0Name: Bob	Student ID: 157367	GPA: 3.5Name: Cam	Student ID: 139581	GPA: 4.0
The honors students are 
Name: Cam	Student ID: 139581	GPA: 4.0
Name: Joe	Student ID: 1578840	GPA: 4.0
*/