Sorting Linked List by Last Name

[mysiarobin1987]

I'm trying to sort my linked list by students' last name (sortLastName function), and it's not working. Can anyone please tell me what I'm doing wrong? Thanks in advance.

PS: Here are the contents of the students.dat file, incase you need it.
Smith Jefferey 891789 [e-mail] 3.75
Lee Jackson 3678902 [e-mail] 3.66
Gonzales Mariana, 168790 [e-mail] 4.0
Jones Mike 8973125 [e-mail] 3.1
Williams Anita 2985465 [e-mail] 3.64
Ronsinson Taylor 3278976 [e-mail] 3.55
Clark Allen 1094567 [e-mail] 3.48
Turner Tavon 318796 [e-mail] 3.2
Jenkins Nelson 289563 [e-mail] 3.0

using namespace std;

#include <iostream>
#include <fstream>
#include<string>
struct student;
typedef student * studentptr, * head, * tail;

struct student
{
	string firstName;
	string lastName;
	unsigned int studentID;
	string email;
	float gpa;
	studentptr next;
};

class studentsProc // Definition of class named studentsProc
{
	public:
		studentsProc();
		void loadList(); // Function that loads data from a data file into a student list
		void printList();
		void retrieveStudent();
		void insertStudent();
		void deleteStudent();
		void printStudent();
		void sortLastName();
		void sortGPA();
		void insertOrder(studentptr s);
		void printSortedList(studentptr sortedStudents);
	
	private:
		student * students; // Pointer to the list of students
		void print() const; //Print the contents of the list
};

studentsProc::studentsProc()
{
	students = NULL;
}

void studentsProc::loadList()
{
	ifstream infile;
	infile.open("students.dat");
	students = NULL; //head pointer points no where
	student temp;
	studentptr temp_ptr;
	while (!infile.eof())
	{
		temp_ptr = new student;
		infile >> temp_ptr->lastName >> temp_ptr->firstName >> temp_ptr->studentID >> temp_ptr->email >> temp_ptr->gpa;//place data in the node
		temp_ptr->next = students;
		students = temp_ptr;
	}
	infile.close();
	
}

void studentsProc::retrieveStudent()
{
	string lastName;
	cout << endl;
	print();
	cout << endl;
	cout << "Please Enter the Last Name of the Student's Information you Wish to Retrieve: " << endl;
	cin >> lastName;
	cout << endl << "Here is the Information You Requested: " << endl;
	for (studentptr s = students; s != NULL; s = s->next)
	if(lastName==s->lastName)
	{
		cout << "Student Name: " << s->lastName << ", " << s->firstName << endl << endl;
	}
}

void studentsProc::insertStudent()
{
	studentptr temp = new student;
	
	cout << endl;
	cout << "Please Enter the Following Information About The New Student: " << endl;
	cout << "Last Name: "; cin >> temp->lastName;
	cout << "First Name: "; cin >> temp->firstName;
	cout << "Student ID: "; cin >> temp->studentID;
	cout << "E-Mail: "; cin >> temp->email;
	cout << "GPA: "; cin >> temp->gpa;
	cout << endl;
	temp->next = students;
	students = temp;
	cout << "The Student List Including the New Student's Information: " << endl;
	printList();
}

void studentsProc::deleteStudent()
{
	cout << endl;
	studentptr prev, pos;
	string lastName;
	bool done = false;
	pos = NULL;
	prev = NULL;
	print();
	cout << endl;
	cout << "Please Enter the Student's Last Name you Wish to Delete: " << endl;
	cin >> lastName;
	cout << endl;
	for (studentptr s = students; (s != NULL) && (done == false); s = s->next)
	{
		if (s->lastName == lastName)
		{
			done = true;
			pos = s;
		}
		else
		{
			prev = s;
		}
	}
	if(prev != NULL)
	{
		prev->next = pos->next;
	}
	else
	{
		students = students->next;
	}
	cout << "The Student List Excluding the New Student's Information: " << endl;
	printList();
}

void studentsProc::printList()
{
	cout << endl;
	for (studentptr s = students; s != NULL; s = s->next)
	cout << "First Name: " << s->firstName << " * "
	<< "Last Name: " << s->lastName << " * "
	<< "Student ID: " << s->studentID << " * "
	<< "E-Mail: " << s->email << " * "
	<< "GPA: " << s->gpa << endl;
}

void studentsProc::sortLastName()
{
	studentptr sortedStudents = NULL;
	
	for (studentptr s = students; s!= NULL; s=s->next)	
	{
		insertOrder(s);
	}
}

void studentsProc::insertOrder(studentptr node)
{
studentptr prev, pos;
studentptr temp = new student;
studentptr sortedStudents = NULL;
bool done = false;
pos = NULL;
prev = NULL;
temp->lastName = node->lastName;
temp->firstName = node->firstName;
temp->studentID = node->studentID;
temp->email = node->email;
temp->gpa = node->gpa;
temp->next = NULL;
for (studentptr s = sortedStudents; (s!=NULL) && (done == false); s=s->next)
{
	if (s->lastName > temp->lastName)
		{
			done = true;
			pos = s;
		}
	else
		{
			prev = s;
		}
}

	if (pos == NULL)
		{
			sortedStudents=temp;
			temp->next = NULL;
		}
	else if (prev == NULL)
		{
			temp->next = sortedStudents;
			sortedStudents = temp;
		}	
	else
		{
			prev->next = temp;
			temp->next = pos;
		}	
	printSortedList(sortedStudents);
}

void studentsProc::printSortedList(studentptr sortedStudents)
{
	cout << endl;
	for (studentptr s = sortedStudents; s != NULL; s = s->next)
	cout << "First Name: " << s->firstName << " * "
	<< "Last Name: " << s->lastName << " * "
	<< "Student ID: " << s->studentID << " * "
	<< "E-Mail: " << s->email << " * "
	<< "GPA: " << s->gpa << endl;
}

void studentsProc::sortGPA()
{
	
}

void studentsProc::printStudent()
{
	string lastName;
	cout << endl;
	print();
	cout << endl;
	cout << "Please Enter the Last Name of the Student's Information you Wish to Retrieve: " << endl;
	cin >> lastName;
	cout << endl << "Here is the Information You Requested: " << endl;
	for (studentptr s = students; s != NULL; s = s->next)
	if(lastName==s->lastName)
	{
		cout << "Last Name: " << s->lastName << " * " 
		<< "First Name: " << s->firstName << " * " 
		<< "Student ID: " << s->studentID << " * " 
		<< "E-mail: " << s->email << " * " 
		<< "GPA: " << s->gpa << endl;
	}
	cout << endl;
}

void studentsProc::print() const
{
	cout << "Student List of Names: " << endl;
	for (studentptr s = students; s != NULL; s = s->next)
	cout << "Last Name: " << s->lastName << " * "
	<< "First Name: " << s->firstName << endl;
}	
int main()
{
	int choice;
	studentsProc student;
	student.loadList();
	    do
    {
      // Menu options to carry out specific operations for student list
      cout << "Please Choose an Option from this Menu" << endl << endl;
      cout << "1. Retrieve and Print a Student from the Student List " << endl;
      cout << "2. Insert a Student into the Student List " << endl;
      cout << "3. Delete a Student from the Student List " << endl;
      cout << "4. Print the Contents of a Student Record " << endl;
      cout << "5. Print the Contents for a List of Students " << endl;
      cout << "6. View the Students List Sorted by Last Name " << endl;
      cout << "7. View the Students List Sorted by GPA " << endl;
      cout << "8. Exit the Program" << endl;
      cin >> choice; // Asks user to input their choice
      
      // Switch menu that carries out the specific operations for student list based on the user's input
      switch (choice) 
      {
             case 1:     student.retrieveStudent(); // Function call to retrieve and print a student's information from the student list
             			 break;
             case 2: 	 student.insertStudent(); // Function call to insert a student's information into the student list
             			 break;
             case 3:	 student.deleteStudent(); // Function call to delete a student's information from the student list
             			 break;
             case 4: 	 student.printStudent(); // Function call to print the contents of a student's record
             			 break;
             case 5: 	 student.printList(); // Function call to print the contents for a list of students
             			 break;
             case 6:	 student.sortLastName(); // Function call to sort the student list by students' last names
             		     break;
             case 7:     student.sortGPA(); // Function call to sort the student list by students' GPAs
			 			 break;   
			 case 8: 	 exit(0); 		    
             default:    cout << "Please enter a value 1-8" << endl; // Default case in which user does not enter a number between 1 and 8, asks user to reenter value
      }//end switch
   } while (choice != 9);
	
return 0;
}

[TheIdeasMan]

and it's not working

What is not working? Be specific about the problems you are having. Have you investigated using a debugger?

Can you tell what the verb is in insertOrder ?

Consider using nullptr instead of NULL.

How many times will the do loop run?

The comments don't give any extra information. If the functions & variables are named well, the code should tell a story of what is happening. Put comments if something is unusual, and / or why something is being done. Also for valid ranges of input.

Hope this helps :+) Good Luck !!

[mysiarobin1987]

When i run the program it compiles, but does not sort the list by last name. Thank you for your suggestions i will try them :-)