1. trigraph ??= is for # ??( is for [ ??< is for { ??! is for |

2. tokens Smallest individual unit is token Keyword e.g. float while
Identifier e.g. main,amount
Constant e.g. 100
String
Special symbol e.g [] {}
operator

3. Keyword & identifier,variable
Keyword have Fixed meaning
Rules for identifier : - first character alphabet - only letters , digit and underscore - only 31 characters - con not use keyword - no white space

4. constant

5. Character & string
Character : ‘c’ - printf(“%i”,’c’); => will print printf(“%c”,’99’); => will print c
String : “c”
Escape sequence : \n, \t

6. Data types Primary data type: int, float
User defined : tyepdef int unit; unit salary;
Derived data tyepe : array,function,structure

7. Data types

8. operators

11. Bitwise operator

12. showbits( )

13. One’s Complement Operator

14. Right Shift Operator

15. Left Shift Operator

16. Bitwise AND Operator

17. Bitwise OR Operator

20. Operator Precedence

21. C is middle level language
Programming efficiency like high level language and
Machine efficiency like low level language

22. Local and global variable
Local variable : declared inside block or function and variable is accessible in block only
Global variable : declared in program accessible everywhere in program
Life time of variables

23. Local variables Global variables Declared inside function body
Scope local to function
Not initialized value
variable with same in different function is possible
Advisable to use
Void main() { int i=4; }
Declared outside function body
Start to end of program
Auto initialized to 0
variable with same in different function is NOT possible
Creates difficulty in debugging
Int i=1; Void main() { //code }

24. Storage classes Storage class defines scope and life time of variable
Storage class decides location of variable : Memory or CPU registers variable’s
storage class tells us:
- Where the variable would be stored.
- What will be the initial value of the variable, if initial value is not specifically assigned.(i.e. the default initial value).
- What is the scope of the variable; i.e. in which functions the value of the variable would be available.
- What is the life of the variable; i.e. how long would the variable exist.

25. Automatic Storage Class

26. Register Storage Class

27. Static Storage Class Storage : Memory. Default initial value : Zero.
Scope : Local to the block in which the variable is defined
Life : Value of the variable persists between different function calls.

29. External Storage Class