Problem
Write function named "findVariables" that accepts a vector of Variable object pointers and a search string. It will return the list of Variable object pointers that contains that search string.
Note that the list can contain pointers to Variable, VariableString or VariableInt objects or any of its derived class objects.
Build a list of pointers pointing to mixed objects of Variable, VariableString and VariableInt objects and show your function returns the mix of three different types.