1. C LANGUAGE Characteristics of C · Small size
· Extensive use of function calls
· Loose typing -- unlike PASCAL
· Structured language
·Pointer implementation - extensive use of pointers for memory, array, structures and functions.

2. C Program Structure Preprocessor Commands Type definitions
Function prototypes -- declare function types and variables passed to function
Variables
Functions

3. Creating, Compiling and Running Your Program
Use any ordinary editor with which you are familiar to create the file
The filename must by convention end ``.c'' (full stop, lower case c), e.g. myprog.c

4. The C Compilation Model
Source code
Preprocessor
Compiler
Assembly code
Assembler
libraries
Object code
Link Editor
Executable code

5. The Preprocessor
The Preprocessor accepts source code as input and is responsible for
removing comments
interpreting special preprocessor directives denoted by #.
C Compiler
The C compiler translates source to assembly code
Assembler
The assembler creates object code

6. Variables C type Size (byte) Unsigned char 1 Short int 2
Unsigned short int
(long) int
float
double

7. Arithmetic Operations
Increment & Decrement operations
Postfix and Prefix expressions
example:- x++ is faster than x=x+1.

8. Order of Precedence () [ ] -> . * / % + - < <= >= >
() [ ] -> .
* / %
+ -
< <= >= >
== !=
& ^
&& || ,

9. CONDITIONALS IF STATEMENT ? OPERATOR SWITCH STATEMENT
break and continue
C provides two commands to control how we loop:
·         break -- exit form loop or switch.
continue -- skip 1 iteration of loop

10. FUNCTIONS { localvariables functioncode } VOID FUNCTIONS
returntype fn_name(1, parameterdef2,…) {
localvariables
functioncode }
VOID FUNCTIONS

11. Structures Collection of different datatypes.
A structure is a user-defined data type.
A structure is a collection of one or more variables, possibly
of different types, grouped together under a single name
Eg: struct student {
int rollno;
char name[10];
float marks;
} s ;

12. UNIONS
A union is a variable which may hold (at different times) objects of different sizes and types .
union number {
short shortnumber;
long longnumber;
double float number; }

13. * POINTERS C uses pointers a lot. Why?:
·         It is the only way to express some computations.
·         It produces compact and efficient code.
·         It provides a very powerful tool.  
What is a Pointer?
A pointer is a variable which contains the address in memory of another variable .

14. Dynamic Memory Allocation
Dynamic allocation is a pretty unique feature to C .
It enables us to create data types and structures of any size and length to suit our programs need within the program.
Malloc
Calloc
Realloc

15. FILES Files are the most common form of a stream Open a file:
FILE *fopen(char *name, char *mode)
fopen returns a pointer to a FILE.
*name ?? *mode ??
Reading and writing files
The functions fprintf and fscanf a commonly used to access files.  
int fprintf(FILE *stream, char *format, args..)
int fscanf(FILE *stream, char *format, args..)

16. Basic String Handling Functions
strcmp
strcat
strcpy
strlen
strerror
strcasecmp

17. DATA STRUCTURES Definition of data structures
• Many algorithms require that we use a proper representation of data to achieve efficiency.
• This representation and the operations that are allowed for it are called data structures.
• Each data structure allows insertion, access, deletion etc.

18. Why do we need data structures?
• Data structures allow us to achieve an important goal: component reuse
• Once each data structure has been implemented once, it can be used over and over again in various applications.

19. Common data structures are
• Stacks
• Queues
Lists
Trees
Graphs
Tables

20. SORTING TECHNIQUES Bubble sort Quick sort Insertion sort
Selection sort
Heap sort