Header files of c++ unit 3 -topic 3

XI-XII unit 3 computer science ppt

1. Header Files of C++ Header files contain definitions of  Functions and Variables , which is imported or used into any C++ program by using the pre-processor #include statement. Header file have an extension ".h" which contains C++ function declaration and macro definition . Why need of header files When we want to use any function in our C++ program then first we need to import their definition from C++ library, for importing their declaration and definition we need to include header file in program by using #include. 

2. Stdio.h Input and Output operations can also be performed in C++ using the C Standard Input and Output Library ( cstdio , known as  stdio.h  in the C language).  When you include iostream.h file in your program ,this file i.e , stdio.h automatically gets included in your program.

3. < iostream.h > S tandard Input / Output Streams Library. Cin Standard input stream  (object ) Cout Standard output stream  (object )

4. < conio.h > conio.h header used in c programming contains functions for console input/output. console  is a term used for the black window, which is also called as command prompt. Some of the most commonly used functions of conio.h are clrscr , getch,etc .

5. < iomanip.h > This file declares services useful for performing formatted I/O with so-called parameterized stream manipulators, such as  setw and  setprecision . setprecision - Sets the  decimal precision  to be used to format floating-point values on output operations. Setw - Sets the  field width  to be used on output operations. The operator used for taking the input is known as the  extraction  or get  from operator  (>>), while the operator used for displaying the output is known as the  insertion  or  put to operator  (<<).

6. Example of setprecision

7. Example of setw

8. Stringh.h

9. < math.h > Most of the mathematical functions are defined in  math . h  ( cmath header in C++). The functions that operate on integers, such as abs , labs , div , and ldiv , are instead defined in the stdlib. h  header ( cstdlib header in C++).

10. < stdlib.h > This header defines several general purpose functions, including dynamic memory management, random number generation, communication with the environment, integer arithmetics , searching, sorting and converting.

11. rand