1: stdio.h
Input/Output functions
2: conio.h
Console Input/Output functions
3: stdlib.h
General utility functions
4: math.h
Mathematics functions
5: string.h
String functions
6: ctype.h
Character handling functions
7 :time.h
Date and time functions
8: float.h
Limits of float types
9: limits.h
Size of basic types
10: wctype.h
Functions to determine the type contained in wide character data.
