The Question
What are the origins of the Public/Private function paradigm?
Background
A question came up in chat about Header files in C, and their usage being mainly to help the compiler, not the programmer. It's my understanding though, that this is the first usage of the concept of "Private" functions, or functions which aren't prototyped in the header file. Had C not used header files to declare functions, would we still have the current concept of Public and Private functions as seen in C# or Java? Or was this concept initially developed elsewhere and simply implemented in the C Header/Source scheme