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Library Functions

C++ compilers include built-in functions to make programming easier.  The number and type of functions available to you depends upon the compiler you are using.  These functions that come with the compiler are called "built-in" library functions.

Library functions are just like the functions that you, as the programmer, create and are used in a similar manner.  The only difference is that the source code (definition) for library functions does NOT appear in your program.  The prototype for the library function is provided to your program using the #include compiler directive.

There are dozens of libraries of  functions available for your use.  We will only be scratching the surface with our use of the most common library functions.

Libraries under discussion at this time:

<ctype.h>  Character classification
and conversion
<math.h>  Math functions
<stdlib.h>  Data conversion
<time.h> Time functions



Using Library Functions
To use a library function, you simply need to include the proper header file and know the name of the function that you wish to use.