[Solved] c++ compilation error: call of overloaded ‘(char*&)’ is ambiguous [closed]

In your cpp file specify the namespace RabQavSystem in your definitions of dateTimeXXX functions.

int RabQavSystem::dateTimeDifference(DateTime datetime1, DateTime datetime2) 
{
    ...
}

int RabQavSystem::dateTimeToMinutes(DateTime datetime)
{
    ...
}