change this code to stl: #include

#include

#include

#include

using namespace std;

ifstream infile;

struct studentNode

$\{$

string firstName;

string lastName;

string id;

double gpa;

studentNode $*$ next;

$\}$;

class studentList

$\{$

studentNode $*$ students;

public:

void addStudent$($studentNode$)$;

void deleteStudent$($studentNode$*,$ studentNode$*)$;

void locateStudent$($string id$,$ bool &end, studentNode $*$&curr, studentNode $*$&prev$)$;

void changeStudent$($string$,$ bool, double, studentNode $*$curr$)$;

void print$()$;

$\}$;

void studentList::addStudent$($studentNode studentRec$)$

$\{$

studentNode $*$temp $=$ new studentNode;

$*$temp $=$ studentRec;

temp$->$next $=$ students;

students $=$ temp;

$\}$

void studentList::deleteStudent$($studentNode $*$curr$,$ studentNode $*$prev$)$

$\{$

if $($prev $==$ NULL$)\{$

students $=$ students $->$ next;

$\}$

else if $($curr $==$ NULL$)\{$

prev $->$ next $=$ NULL;

$\}$

else$\{$

prev $->$ next $=$ curr $->$ next;

$\}$

$\}$

void studentList::locateStudent$($string id$,$ bool &end, studentNode $*$&curr, studentNode $*$&prev$)$

$\{$

for $($studentNode $*$s $=$ students; $($s$!=$ NULL$)$ && $($end $==$ false$)$; s $=$ s $->$ next$)\{$

if $($s $->$ id $==$ id$)\{$

end $=$ true;

curr $=$ s;

$\}$

else

prev $=$ s;

$\}$

$\}$

void studentList::changeStudent$($string id$,$ bool end, double gpa, studentNode $*$curr$)$

$\{$

if $($end $==$ true$)\{$

curr $->$ gpa $=$ gpa;

$\}$

else if $($end $==$ false$)\{$

curr $==$ NULL;

cout $<<"$ Student ID $"<<$ id $<<"$ not found" $<<$ endl;

$\}$

$\}$

void studentList :: print$()$

$\{$

for$($studentNode $*$s $=$ students; s $!=$ NULL; s $=$ s$->$next$)\{$

cout $<<$ s$->$firstName $<<""<<$ s$->$lastName $<<""<<$ s$->$id $<<""<<$ s$->$gpa $<<$ endl;

$\}$

cout $<<$ endl;

$\}$

void processAdd$($studentList &students$)$

$\{$

studentNode s;

infile $>>$ s$.$firstName;

infile $>>$ s$.$lastName;

infile $>>$ s$.$id;

infile $>>$ s$.$gpa;

students.addStudent$($s$)$;

$\}$

void processDelete$($studentList &students$)$

$\{$

bool end $=$ false;

string id;

studentNode $*$curr $=$ NULL;

studentNode $*$prev $=$ NULL;

infile $>>$ id;

students.locateStudent$($id $,$end $,$curr $,$prev$)$;

if $($end $==$ true$)\{$

students.deleteStudent$($curr$,$prev$)$;

cout $<<$ "Student ID: $"<<$ id $<<"$ has been deleted" $<<$ endl;

$\}$

else if $($end $==$ false$)\{$

cout $<<$ "Student cannot be found." $<<$ endl;

$\}$

cout $<<$ endl;

$\}$

void processSearch$($studentList &students$)$

$\{$

bool end $=$ false;

string id;

studentNode $*$curr $=$ NULL;

studentNode $*$prev $=$ NULL;

infile $>>$ id;

students.locateStudent$($id$,$end,curr,prev$)$;

if $($end $==$ true$)\{$

cout $<<$ "Information Located: $"<<$ curr $->$ firstName $<<""<<$ curr $->$ lastName $<<""<<$ curr$->$id $<<""<<$ curr$->$ gpa $<<$ endl;

$\}$

else$\{$

cout $<<$ "Information: $"<<$ id $<<"$ cannot be found.";

$\}$

$\}$

void processChange$($studentList &students$)$

$\{$

bool end $=$ false;

string id;

double gpa;

studentNode $*$curr $=$ NULL;

studentNode $*$prev $=$ NULL;

infile $>>$ id;

students.locateStudent$($id$,$end,curr,prev$)$;

$\}$

int main$()$

$\{$

char code;

studentList students;

infile.open$("$updates$.$txt$")$;

while $(!$infile.eof$())$

$\{$

infile $>>$ code;

if $($code $==\text{'}$A$\text{'}||$ code $==\text{'}$a$\text{'})$

$\{$

processAdd$($students$)$;

students.print$()$;

$\}$

else if $($code $==\text{'}$D$\text{'}||$ code $==\text{'}$d$\text{'})$

$\{$

processDelete$($students$)$;

students.print$()$;

$\}$

else if $($code $==\text{'}$S$\text{'}||$ code $==\text{'}$s$\text{'})$

processSearch$($students$)$;

else if $($code $==\text{'}$C$\text{'}||$ code $==\text{'}$c$\text{'})$

$\{$

processChange$($students$)$;

students.print$()$;

$\}$

else

$\{$

cout $<<$ "Invalid code $"<<$ code $<$