Returning a value if object not found in the array c++

So this is my code:

for (Customer c : customers) {
    if (custID == c.getCustID()) {
        return c;
    }   
}

I am looking to be able to return some value if what is entered on the console does not match what is listed in the customers array

customers[]

This is from the source code which the user input if coming from:

int x = 0;
cout << "Please enter the customer ID!" << endl;
cin >> x;
Customer c = MyDataStore::getCustomer(x);
cout << c.print();

At this moment if the user enters a number which is listed in the array then it returns the correct value but I want a safe fall for when they enter an invalid number. Thank you!