I need help, when I put the preloaded user, the program works normally, but I need that if I put a wrong user it gives me the option to add user, and asks me for the user again, so when I put the one I added as new, it works normally.

Here my code

int main$()\{$

vector items $=\{$

Item$("$Paper$",50),$

Item$("$Feather$",20),$

Item$("$Laptop$",100),$

Item$("$Pencil$",10),$

Item$("$Draft$",5)$

$\}$;

vector cart;

string inputUser, inputPass;

cout $<<$ "User: $"$;

cin $>>$ inputUser;

cout $<<$ "Password: $"$;

cin $>>$ inputPass;

if $($User::validateUser$($inputUser$,$ inputPass$))\{$

cout $<<"---$ Welcome to my online store $---"<>$ choice;

switch $($choice$)\{$

case $1$: $\{$

int subChoice;

cout $<<"1.$ View items below a certain price" $<<$ endl;

cout $<<"2.$ View items above a certain price" $<<$ endl;

cout $<<"3.$ Search by name" $<<$ endl;

cout $<<$ "Enter your choice: $"$;

cin $>>$ subChoice;

if $($subChoice $==1||$ subChoice $==2)\{$

double priceLimit;

cout $<<$ "Enter price limit: $"$;

cin $>>$ priceLimit;

cout $<<$ "Available items:

$"$;

for $($int i $=0$; i $<$ items.size$()$; i$++)\{$

if $(($subChoice $==1$ && items$[$i$].$getPrice$()<$ priceLimit$)||($subChoice $==2$ && items$[$i$].$getPrice$()>$ priceLimit$))\{$

cout $<<$ i $+1<<"."<<$ items$[$i$].$getName$()<<"-$ Price: $$"<<$ items$[$i$].$getPrice$()<<$ endl;

$\}$

$\}$

$\}$

else if $($subChoice $==3)\{$

string itemName;

cout $<<$ "Enter item name: $"$;

cin $>>$ itemName;

for $($const auto & item : items$)\{$

if $($item$.$getName$()==$ itemName$)\{$

cout $<<$ "Item: $"<<$ item.getName$()<<",$ Price: $$"<<$ item.getPrice$()<<$ endl;

$\}$

$\}$

$\}$

char addToCart;

cout $<<"$Do you want to add an item to your cart? $($Y$/$N$)$: $"$;

cin $>>$ addToCart;

if $($addToCart $==\text{'}$Y$\text{'}||$ addToCart $==\text{'}$y$\text{'})\{$

int itemNumber;

int itemQuantity;

cout $<<$ "Enter item number: $"$;

cin $>>$ itemNumber;

cout $<<$ "Enter the amount: $"$;

cin $>>$ itemQuantity;

if $($itemNumber $>0$ && itemNumber $<=$ items.size$())\{$

items$[$itemNumber $-1].$setQuantity$($itemQuantity$)$;

cart.push$\_$back$($items$[$itemNumber $-1])$;

cout $<<$ "Item added to cart." $<<$ endl;

$\}$

else $\{$

cerr $<<$ "Invalid item number." $<<$ endl;

$\}$

string cont;

cout $<<"$Do you want to exit to the main menu or continue adding items?$($Menu$/$Add$)$: $"$;

cin $>>$ cont;

while $($cont $==$ "Add"$)\{$

int itemNum, qty;

cout $<<$ "Enter item number: $"$;

cin $>>$ itemNum;

cout $<<$ "How many pieces?";

cin $>>$ qty;

items$[$itemNum $-1].$setQuantity$($qty$)$;

cart.push$\_$back$($items$[$itemNum $-1])$;

cout $<<$ "Item added to cart.

$"$;

cout $<<"$Do you want to exit to the main menu or continue adding items?$($Menu$/$Add$)$: $"$;

cin $>>$ cont;

$\}$

$\}$

break;

$\}$

case $2$: $\{$

cout $<<$ "Your cart:" $<<$ endl;

double total $=0$;

for $($size$\_$t i $=0$; i $<$ cart.size$()$; i$++)\{$

cout $<<($i $+1)<<"."<<$ cart$[$i$].$getName$()<<",$ Price: $$"<<$ cart$[$i$].$getPrice$()<<",$ Quantity: $"<<$ cart$[$i$].$getQuantity$()<<$ endl;

total $+=$ cart$[$i$].$getPrice$()*$ cart$[$i$].$getQuantity$()$;

$\}$

cout $<<$ "Total cost: $$"<<$ total $<<$ endl;

string checkout;

cout $<<"$Do you want to pay or continue shopping?? $($Pay$/$Continue$)$: $"$;

cin $>>$ checkout;

if $($checkout $==$ "Checkout"$)\{$

cout $<<$ "Press Ok to close the sale..

$"$;

string Ok;

cin $>>$ Ok;

if $($Ok $=="$Ok$")\{$

cout $<<$ "Sale successfully closed. Thank you for shopping with us$!"<<$ endl;

cart.clear$()$;

$\}$

$\}$

break;

$\}$

case $3$:

cout $<<$ "Goodbye!" $<<$ endl;

break;

default:

cerr $<<$ "Invalid choice." $<<$ endl;

break;

$\}$

$\}$

while $($choice $!=3)$;

$\}$

else $\{$

cerr $<<$ "Unregistered user." $<<$ endl;

cout $<<""<<$ endl;

string register;

cin $>>$ register;

if $($register $=="*")\{$

string username, password;

cout $<<$ "Enter your username: $"$;

cin $>>$ username;

cout $<<$ "Enter your password: $"$;

cin $>>$ password;

$\}$

$\}$

return $0$;

$\}$