Hello. I am creating a ring class which has a collection of items $($vector$)$ that has a reference to a current item in that vector. I am trying to implement the following operations $($methods$)$ within this class. They are:

advance$(),$ which advances the reference to the next object in the list by one, until it gets to the end, when it again references the first object in the vector.

getCurrentItem$(),$ which, when called will get the currently referenced item in the vector.

addItem$(),$ which will add a new item to the vector, increasing its size by $1$

removeItem$(),$ which will delete an item from the vector, decreasing its size by $1$

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With my current code, I find that I am able to advance and get the current item as long as I do not add or delete an item, or am not at the end of the vector. If I do add or delete an item, or am at the end of the vector, it gives me a memory allocation error. I am not sure why I am getting this memory allocation error. Can you please help. Many thanks. Below is my current code.

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#include

#include

#include

#include

#include

#include

#include

using namespace std;

class Ring

$\{$

private:

vector m$\_$objectList;

string$*$ pStr $=$ &$($m$\_$objectList$[0])$;

public:

Ring$($vector list$)$ : m$\_$objectList$($list$)$

$\{$

$\}$

vector getVector$()$

$\{$

return m$\_$objectList;

$\}$

void advanceItem$()$

$\{$

int i $=0$;

if $($i $!=$ m$\_$objectList.size$()-1)$

$\{$

pStr$++$;

$\}$

else

$\{$

pStr $=$ &$($m$\_$objectList$[0])$;

$\}$

$\}$

string getCurrentItem$()$

$\{$

return $*$pStr;

$\}$

void addItem$($int index, string addedItem$)$

$\{$

m$\_$objectList.insert$($m$\_$objectList.begin$()+$ index, addedItem$)$;

$\}$

void removeItem$($int index$)$

$\{$

m$\_$objectList.erase$($m$\_$objectList.begin$()+$ index$)$;

$\}$

$\}$;

int main$()$

$\{$

Ring myList$(\{$ "seven", "one", "nine", "twelve" $\})$;

cout $<<$ myList.getCurrentItem$()<<$ endl;

myList.advanceItem$()$;

cout $<<$ myList.getCurrentItem$()<<$ endl;

myList.addItem$(2,$ "three"$)$;

cout $<<$ myList.getCurrentItem$()<<$ endl;

myList.advanceItem$()$;

myList.advanceItem$()$;

cout $<<$ myList.getCurrentItem$()<<$ endl;

myList.advanceItem$()$;

cout $<<$ myList.getCurrentItem$()<<$ endl;

myList.advanceItem$()$;

cout $<<$ myList.getCurrentItem$()<<$ endl;

for $($int i $=0$; i $<$ myList.getVector$().$size$()$; i$++)$

$\{$

cout $<<$ myList.getVector$().$at$($i$)<<""$;

$\}$

return $0$;

$\}$