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. return
11. switch
12. while
13. case
14. double
15. goto
16. short
17. typedef
18. char
19. else
20. if
21. signed
22. union
23. const
24. enum
25. int
26. sizeof
27. unsigned
28. continue
29. extern
30. long
31. static
32. 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