Program-Subprogram Structure

How are Subprograms (Procedures, Functions) organized in a Program?

Separate Subprogram Definition: FORTRAN
Must declare even global (COMMON) variables
Separate Interface: C
Header file independently is compilable
Nested Subprogram Definition: Pascal
Type-checkable non-local referencing environment provided
Separate Data Definition: C++
Classes have data + functions
Data Definition Apart From Executables: COBOL
Program separated into (global) Data, Procedure, Environment divisions
Unseparated Subprogram Definitions: BASIC
Subprograms implemented using GOTOs