difference between regular file and pipe file in unix
Unix file types These named pipes are special files that can exist anywhere in the file system. These named pipe special files are made with the command mkfifo as in mkfifo mypipe.
Include directive In C and C++, the #include preprocessor directive causes the compiler to replace that line with the entire text of the contents of the named source file (if included in quotes: "") or named header (if included in angle brackets: <>);[1] note that a header need not be a source file.[2] Inclusion continues recursively on these included contents, up to an implementation-defined nesting limit. Headers need not have names corresponding to files: in C++ standard headers are typically identified with words, like "vector", hence #include <vector> while in C standard headers have identifiers in the form of filenames with a ".h" extension, as in #include <stdio.h>. A "source file" can be any file, with a name of any form, but is most commonly named with a ".h" extension and called a "header file" (sometimes ".hpp" or ".hh" to distinguish C++ headers), though files with .c, .cc, and .cpp extensions may also be included (particularly in the Single Compilation Unit technique), and sometimes other extensions are used.