Data Types :

Basic Data Types :

Data Types	Occupied in RAM
char int float double	1byte 2bytes 4bytes 8bytes

Additional Data Types :

Data Types	Occupied in RAM
unsigned char short int unsigned short int unsigned int long int unsigned long int long double	1byte 1byte 1byte 2bytes 4bytes 4bytes 10bytes

Format Specifiers :

Data Type	Format	Meaning
int	%d %u %o %x	Respects a decimal integer value. Respects an unsigned integer value. Respect an unsigned octal value. Respect an unsigned hexadecimal value.
float / double	%f %e	Represents a floating point value. A floating point value in decimal or exponential form.
char	%c %s	Represents a single character value. Represents a strings of value of characters.

Note : %hd, %ld, %lf are used for short int, long int and long double respectively.

Keywords Or Reserved Words :

1. auto
2. default
3. float
4. register
5. struct
6. volatile
7. break
8. do
9. for
10. for
11. return
12. switch
13. while
14. case
15. double
16. goto
17. short
18. short
19. typedef
20. char
21. else
22. if
23. signed
24. union
25. const
26. enum
27. int
28. sizeof
29. unsigned
30. continue
31. extern
32. long
33. static
34. void

Character Constant :

Character Constant	Meaning
\n	Move to new line
\r	Carriage return (Enter)
\t	Horizontal tab
\v	Vertical tab
\\	Print back slash
\?	Print qustion mark
\'	print singel quote
\"	print double quote
\0	Null character