1. by Anand George SourceLens.org Copyright. All rights reserved. Content Owner - Meera R (meera at sourcelens.org)

2. Introduction  Most of the real world programs contain more than 1 source code files.  This is for modularity and manage ability. SourceLens.org Copyright. All rights reserved. Content Owner - Meera R (meera at sourcelens.org)

3. Demo  Multifile C hello world.  New header file creation. SourceLens.org Copyright. All rights reserved. Content Owner - Meera R (meera at sourcelens.org)

4. Some practices  All declaration should be in the header files.  All definitions should be in the Source Files.  Declarations are things which complier look for.  Definitions are things which linker look for.  So normally header file and C files are pairs. Like mymodule1.h ( contains all the declarations of variables and functions) and mymodule.cpp ( contains all the definitions of variables and functions ) SourceLens.org Copyright. All rights reserved. Content Owner - Meera R (meera at sourcelens.org)

5. keyword extern  For declaring global variable which are defined in other C files.  static keyword for file scope. SourceLens.org Copyright. All rights reserved. Content Owner - Meera R (meera at sourcelens.org)

6. Demo  Declaration and definition distinguished.  Generation of complier error and link error.  Global variables and extern keyword.  static variable scope. SourceLens.org Copyright. All rights reserved. Content Owner - Meera R (meera at sourcelens.org)

7. Thank you SourceLens.org Copyright. All rights reserved. Content Owner - Meera R (meera at sourcelens.org)