Coming from Pascal/Delphi background I too find the structured separation useful (unlike the unstructured one in C/C++), though obviously it has a cost of typin

Coming from Pascal/Delphi background I too find the structured separation useful (unlike the unstructured one in C/C++), though obviously it has a cost of typing the declarations twice. Then for more modern languages where there's no separation some IDE's can auto-generate the interface declarations along with the associated comments. E.g. Xcode does it for Swift and it's kind of OK.