Chapter 12: Programming in the Large By: Suraya Alias 1-1

Figure 13.1 Preparing a Program for Execution 1-2

13.1 Using Abstraction to Manage Complexity Procedural Abstraction – Separation of what a function does from the details of how the function accomplished its purposes. – Example ; fopen(), sqrt() function Data Abstraction – Separation of the logical view of a data object (what is stored) from the physical view (how the information is stored) – Example ; data type double Information hiding – Protecting the implementation details of lower-level module from direct access by a higher-level module – Example ; only access data object through operators Encapsulate – Packaging as a unit a data objects and its operator 1-3

13.2 Personal Libraries : Header Files Header file – Has a.h extension, example header.h – Contains the interface information about a library needed by a compiler to translate a program system – Use the #include preprocessor directive 1-4

Figure 13.2 Header File planet.h for Personal Library with Data Type and Associated Functions 1-5

Figure 13.2 Header File planet.h for Personal Library with Data Type and Associated Functions 1-6

Figure 13.3 Portion of Program That Uses Functions from a Personal Library 1-7

13.2 Personal Libraries : Implementation Files Implementation file – File containing the C source code of a library function and other info – Example; if we create a personal library header.h we can include it in hello.c 1-8

Figure 13.4 Implementation File planet.c Containing Library with Planet Data Type and Operators 1-9

Figure 13.4 Implementation File planet.c Containing Library with Planet Data Type and Operators (cont’d) 1-10

13.4 Storage Classes 1.Auto – Default storage class of function parameters and local variables 2.Extern – Function names are of storage class extern – It will be available to the linker 3.Global variable – A variable that may be accessed by many functions in a program 4.Static – Storage class of variables allocated only once, prior to program execution 5.Register – Storage class of automatic variables that the programmer would like to have stored in register 1-11

Figure 13.5 Storage Classes auto and extern as Previously Seen 1-12

Figure 13.5 Storage Classes auto and extern as Previously Seen (cont’d) 1-13

Figure 13.6 Declaration of a Global Variable 1-14 In eg1.c, the declaration allocates space for global_var_x In eg2.c, the keyword extern allocates no memory. It only informs the compiler

Figure 13.7 Use of Variables of Storage Class extern 1-15

13.5 Modifying Functions for inclusion in a Library The exit() function allows premature termination of program execution The break function can be used to terminate a nested loop 1-16

Figure 13.9 Conditional Compilation of Tracing printf Calls 1-17

13.6 Conditional compilation Figure Conditional Compilation of Tracing printf Calls 1-18

Figure Header File That Protects Itself from Effects of Duplicate Inclusion 1-19

Figure Header File That Protects Itself from Effects of Duplicate Inclusion (cont’d) 1-20

Figure Header File That Protects Itself from Effects of Duplicate Inclusion (cont’d) 1-21

Figure File Backup Using Arguments to Function main 1-22

13.7 Arguments to Function Main Command line arguments 1-23

13.7 Defining Macros with Parameters Macro – Facility for naming a commonly used statement or operation Macro expansion – Process of replacing a macro call by its meaning Use of parentheses Extending macro over two or more lines 1-24

Figure Program Using a Macro with Formal Parameters 1-25

Figure Macro Expansion of Second Macro Call of Program in Fig

Figure Macro Calls Showing Importance of Parentheses in Macro Body 1-27

Figure Macro Calls Showing Importance of Parentheses in Macro Body (cont’d) 1-28

Figure Macro Expansions of Macro Calls from Fig

Chapter 13 – Dynamic data Structures 1-30

Pointers Dynamic data structures – A structure that can expand and contract as a program executes Nodes – Dynamically allocated structures that are linked together to form a composite structure 1-31

Pointers Pointers as function parameters – long_division(40, 3, &quot, &rem) Pointers representing arrays and strings – char *n or char n[] Pointers to structures – An array of structures was represented as a pointer to the first array element Refer table

1-33 Figure 14.1 Comparison of Pointer and Nonpointer Variables

1-34 Figure 14.2 Function with Pointers as Output Parameters