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PObubble sorting an array of a class
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  1. PObubble sorting an array of a class
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    copied!<p>I wrote a program that is supposed to read in records from a file and enter them into an array of a Student class. I then need to sort them by name.</p> <pre><code>import java.io.*; import java.util.Scanner; public class StudentTest { public static void main(String[] args) { String name; String address; String major; double gpa; int classLevel; int college; String blank; String idNumber; Scanner fileIn = null; try { fileIn = new Scanner (new FileInputStream("student.dat")); } catch (FileNotFoundException e) { System.out.println("File not found"); System.exit(0); } Student[] aStudent = new Student[15]; int index = 0; for (index=0; index &lt;= 15; index++) { while (fileIn.hasNext()) { name = fileIn.nextLine(); address = fileIn.nextLine(); major = fileIn.nextLine(); gpa = fileIn.nextDouble(); classLevel = fileIn.nextInt(); college = fileIn.nextInt(); fileIn.nextLine(); idNumber = fileIn.nextLine(); aStudent[index] = new Student(name, address, major, gpa, classLevel, college, idNumber); aStudent[index].Display(); } } Student temp = null; for (int pass = 0; pass &lt; (index-1); pass++) { for (int c = 0; c &lt; (index - 1); c++) { if (aStudent[].getName() &gt; aStudent[c+1].getName()) { temp = aStudent[]; aStudent[]=aStudent[+1]; aStudent[+1]=temp; } } } } } import java.util.Scanner; public class Student { private String name; private String address; private String major; private double gpa; private int classLevel; private int college; private String idNumber; Scanner keyboard = new Scanner(System.in); public Student(String name, String address, String major, double gpa, int classLevel, int coll, String idNum) { this.name = name; this.address = address; this.gpa = gpa; this.major = major; this.classLevel = classLevel; this.college = coll; this.idNumber = idNum; } public String getName() { return name; } public String getAddress() { return address; } public String getMajor() { return major; } public double getGPA() { return gpa; } public int getClassLevel() { return classLevel; } public int getCollege() { return college; } public String getID() { return idNumber; } public void setAddress(String address) { } public void setMajor(String maj) { } public void setCollege(int coll) { } public void Display() { System.out.println("Name: "+getName()); System.out.println("Address: "+getAddress()); System.out.println("Major: " + getMajor()); System.out.println("GPA: "+getGPA()+" Class Level: "+getClassLevel()+" College: "+getCollege()); System.out.println("ID: "+getID()); System.out.println("==============================="); } } </code></pre> <p>I wrote the sort the way my proffessor described it in class, but I am still getting errors that "the > operator is undefined for the argument type(s) java.laungage.String"</p> <p>Any help would be greatly appreciated.</p> <p>thanks</p> <p>Edit: I used Ashan's suggestion and now it looks like this.</p> <pre><code> for (int pass = 0; pass &lt; (index-1); pass++) { for (int c = 0; c &lt; (index - 1); c++) { if (aStudent[c].getName().compareTo(aStudent[c+1].getName()) &gt; 0) { temp = aStudent[c]; aStudent[c]=aStudent[+1]; aStudent[+1]=temp; </code></pre> <p>That cleared up that error. However, I am now getting a NullPointerException.</p>
 

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