What is header file in c?

Include directory is special directory which content all the header files of c language. Extension of header files in c language is h. All header files only keep declaration of functions, declaration of data type and micro constants. Body of function i.e. function definition is not written in the header files. Hence no one can get source code of function like printf, clrscr etc. All the function declaration in header file is extern. Since visibility of extern data type is whole the program. Hence other file can also access such function. Body of function of header file is supplied at the time of linking.

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    Anonymous said...

    if definition of functions is not saved in header files,then where these are saved?

    ritesh kumar said...

    Function definition is added at the time of linking. It is saved at compiler.