// Create project instance
System::String dataDir = RunExamples::GetDataDir(System::Reflection::MethodBase::GetCurrentMethod(ASPOSE_CURRENT_FUNCTION)->get_DeclaringType().get_FullName());
System::SharedPtr<Project> project = System::MakeObject<Project>(dataDir + u"Project1.mpp");
project->Set<NullableBool>(Prj::NewTasksAreManual(), NullableBool::to_NullableBool(false));
        
// Create new custom field (Task Text1) with formula which will double task cost
System::SharedPtr<ExtendedAttributeDefinition> attr = ExtendedAttributeDefinition::CreateTaskDefinition(Aspose::Tasks::CustomFieldType::Text, Aspose::Tasks::ExtendedAttributeTask::Text1, u"Custom");
attr->set_Alias(u"Double Costs");
attr->set_Formula(u"[Cost]*2");
project->get_ExtendedAttributes()->Add(attr);
        
// Add a task
System::SharedPtr<Task> task = project->get_RootTask()->get_Children()->Add(u"Task");
        
// Set task cost            
task->Set<System::Decimal>(Tsk::Cost(), static_cast<System::Decimal>(100));
        
// Save project
project->Save(dataDir + u"WriteFormulasInExtendedAttributesToMPP_out.mpp", Aspose::Tasks::Saving::SaveFileFormat::MPP);