Page 98 - Modular_V2.0_C++_Flikpbook
P. 98

9                                                        HEADER FILES AND



                                                                          LIBRARY FUNCTIONS








                         Your Aim


                         to learn about:
                                 Header Files                       Functions of math.h Header File
                                   Functions of stdlib.h Header File          More Solved Programs




                  As you already know that C++ provides built-in functions. Built-in functions are defined inside
                  the header files. Hence, these functions are also called library functions. C++ provides a number
                  of header files to perform different types of operations like mathematical calculations, character
                  manipulations, input/output and error checking.

                     HEADER FILES

                  A header file is a collection of predefined functions that help improve a program’s productivity
                  and save development time. These header files come built-in with the C++ compiler and are
                  known  as  standard  header  files.  The  functions  contained  within  them  are  called  standard
                  library functions.

                  In C++, most header files have the .h extension. Several important header files and their purposes
                  are listed below:

                           Header File                                     Description
                     iostream.h                It provides standard input and output functions.

                     conio.h                   It provides functions for console input/output.
                     math.h                    It provides various functions to perform mathematical operations.

                     ctype.h                   It provides functions to handle characters in C++.
                     stdlib.h                  It provides various functions to perform operations like numbers
                                               to text conversion, text to numbers conversion, memory allocation,
                                               random numbers and various other utility functions.
                  To use any library function in your program, respected header file should be included at the beginning
                  of your program code. You can include a header file in your program by using the preprocessor

                  directive #include followed by name of the header file in between the angular brackets:
                       #include<iostream.h>

                   96
                          Touchpad MODULAR (Ver. 2.0)
   93   94   95   96   97   98   99   100   101   102   103