Singly Linked List in C++ help???

i have sorted singly linked list but my problem is starting after it.i have to print the info within the range defined by user input.i tried i little but i need help.

Code:

void printUserInput()
{	
	char x,y;
	node * temp=head;
	cout<<"Please enter two latter"<<endl;
	cin>>x;
	cin>>y;
	
	if(x>=y)
	{
		cout<<"The second user input must come after the first one."<<endl;
		
	}
	
	else
	{	
		while(temp->surname[0]==x){
			temp=temp->next;
		}
		while(temp->surname[0]==y){
				cout<<temp->id<<" ";
				cout<<temp->surname<<" ";
				cout<<temp->name<<" ";
				cout<<temp->age<<" "<<endl;
				temp=temp->next;
		}
	}
}

 

Code:

#include <iostream>
#include <string>
#include <fstream>
#include <sstream>
#include <cstdlib>

using namespace std;

void selectionSort(string [], int);
void showArray(string [], int);


struct node{
 node * next;
 node * tail;
 node * head;
 int id;
 string name;
 string surname;
 int age;
 
 };

node * thelist = NULL;
node * tail = NULL;
node * head = NULL;

void initList(int id, string surname, string name, int age){
    thelist=new node;
    thelist->next=NULL;
	thelist->id=id;
	thelist->surname=surname;
	thelist->name=name;
	thelist->age=age;
	tail=thelist;
	head=thelist;
}

void addToHead(int newid, string newsurname, string newname, int newage){

    node * mynewnode = new node;
	mynewnode->id=newid;
	mynewnode->surname=newsurname;
	mynewnode->name=newname;
	mynewnode->age=newage;
    mynewnode->next=thelist;
    thelist=mynewnode;
	head=thelist;

	
    //Question : we did not check whether the list is empty or not, why ?
}

void removeFromHead(){
    if(head==NULL){
        return;
    }   
	node * temp = head;
	head=head->next;
    delete temp;
}

node * getNodeFromValue(int searchValue){
    node * temp=thelist;
    while(temp!=NULL && temp->id!=searchValue){
        temp=temp->next;
    }
    return temp;
}

void insertAfterNode(node * mynode,int newid, string newsurname, string newname, int newage){
    
    node * mynewnode = new node;
    mynewnode->id=newid;
	mynewnode->surname=newsurname;
	mynewnode->name=newname;
	mynewnode->age=newage;
    mynewnode->next=mynode->next;
    mynode->next=mynewnode;
}

void addToTail(int newid, string newsurname, string newname, int newage) {
    if (tail != 0) {   
		node * mynewnode = new node;
		mynewnode->id=newid;
		mynewnode->surname=newsurname;
		mynewnode->name=newname;
		mynewnode->age=newage;
		tail->next=mynewnode;
		tail=tail->next;
		tail->next=NULL;
		
    }
    else node * head = tail = new node;
}

void deleteAfterNode(node * mynode){
    if(mynode->next==NULL){
       
        return;
    }
    node * temp=mynode->next;
    mynode->next=mynode->next->next;
    delete temp;
}
void printList(){
    node * temp=head;
    while(temp!=NULL){
        cout<<temp->id<<" ";
		cout<<temp->surname<<" ";
		cout<<temp->name<<" ";
		cout<<temp->age<<" "<<endl;
        temp=temp->next;
    }
    cout<<endl;
}


void sortNodes(node * ptr) {
	string temp ;
	node * curr;
	for(bool Swap = true; Swap; ) {
		Swap = false;
		for(curr = ptr; curr->next != NULL; curr = curr->next) {
			if(curr->surname > curr->next->surname) {
				temp= curr->surname;
				curr->surname = curr->next->surname;
				curr->next->surname = temp;
				Swap = true;
			} 
		}
	}
}


void printUserInput()
{	
	char x,y;
	node * temp=head;
	cout<<"Please enter two latter"<<endl;
	cin>>x;
	cin>>y;
	
	if(x>=y)
	{
		cout<<"The second user input must come after the first one."<<endl;
	}
	
	else
	{	
		while(temp->surname[0]==x){
			temp=temp->next;
		}
		while(temp->surname[0]==y){
				cout<<temp->id<<" ";
				cout<<temp->surname<<" ";
				cout<<temp->name<<" ";
				cout<<temp->age<<" "<<endl;
				temp=temp->next;
		}
	}

}
int main()
{
    
	initList(0,"Surname","Name",0);

	ifstream infile;
	infile.open ("projectsampleDB.txt");
	
	string sString;
	string id;

	while(!infile.eof())
	{
		getline(infile,sString);
		
		int i;

		i=sString.find(" ");
		int tempId=atoi(sString.substr(0,i).c_str());
		sString.erase(0,i+1);

		i=sString.find(" ");
		string tempSurname=sString.substr(0,i);
		sString.erase(0,i+1);

		i=sString.find(" ");
		string tempName=sString.substr(0,i);
		sString.erase(0,i+1);

		int tempAge=atoi(sString.substr().c_str());
		
		addToTail(tempId, tempSurname, tempName, tempAge);
	
	}

	removeFromHead();


	cout<<"Unsorted List : "<<endl;
	printList();
	

	
	cout<<"Sorted List : "<<endl<<endl;

	sortNodes(head);
	printList();

	printUserInput();	
}

# PersonelID Surname Name Age
11098 terzi Emre 25
14894 saglar Isil 45
09993 ozden Egemen 33
.......

myprogram must be able to process this kind of files and insert it into a circular singly
linked list. After reading this file, it must be able to sort the list according to surnames. After
that operation(which i failed), program asks for the user input to enter the start and end user surnames and it
will print the persons in the list whose surname is within that user input (inclusive).