A function is self-contained block of statements that performs particular task. C++ functions can be classified into two types:
The library functions are the functions which are already defined in C++s functions library i.e. header files. For example, the functions clrscr( ) and getch( ) are the library functions defined in file conio.h same as functions sqrt( ) is defined in math.h. User defined function is the function defined by the programmer who has written the program. The task to perform is decided by user.
Need of user-defined function
1. The functional program facilitates top-down modular programming approach as shown in figure below.
2. The length of source program can be reduced by functions at appropriate places.
3. It is easy to locate and isolate a faulty function for further investigations.
4. A function may be used by many other programs. This means that a C++ programmer can build on what others have already done. That is we can reuse the functions already defined in some program files.
- Library functions
- User-defined functions
The library functions are the functions which are already defined in C++s functions library i.e. header files. For example, the functions clrscr( ) and getch( ) are the library functions defined in file conio.h same as functions sqrt( ) is defined in math.h. User defined function is the function defined by the programmer who has written the program. The task to perform is decided by user.
Need of user-defined function
1. The functional program facilitates top-down modular programming approach as shown in figure below.
2. The length of source program can be reduced by functions at appropriate places.
3. It is easy to locate and isolate a faulty function for further investigations.
4. A function may be used by many other programs. This means that a C++ programmer can build on what others have already done. That is we can reuse the functions already defined in some program files.
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