Introduction to object

1 Declarations VS definitions     (Page 81)

    declarations: This function or variable exists somewhere, and here is what it should look like.

    definitions: Make this function here or make this variable here, it allocates storage for the name.

For a variable, the compiler determines how big that variable is and causes space to be generated in memory to hold the data for that variable. For a function, the compiler generates code, which ends up occupying storage in memory.

 

2 Extern          (Page 84)

3 Include          (Page 85)

include <>: there's some kind of "include search path" that you specify in your environment or on the compiler command line.

include "": Search for the file relative to the current directory. If the file is not found, then the include directive is reprocessed as if it has angle brackets instead of quotes.

4 Linking         (Page 87)

4.1 Using libraries         (Page 88)

    step1 Include the library's header file.

    step2 Use the functions and variables in the library.

    step3 Link the library into the executable program.

If you are using an add-on library, you must explicitly add the library name to the list of files handed to the linker.

5 Using namespace

    The using directive expose only those names for the current file.

6 main

In C++, main() always has return type of int.

7 iostreams

8 Calling other programs

system();                   //<cstdlib>