Demonstrate the use of functions in C and Cpp?

Answer 1

Functions have several purposes. Every program must have at least one global function named main. Although it is possible to write entire programs using this one function, this is only practical with extremely trivial applications, such as the "Hello World" application:

int main()

{

cout << "Hello world!";

}

As programs become more and more complex, however, we need to break the program down into much simpler problems, such that our main function actually does very little work. Typically, the main function does nothing more than call a function to process the command line arguments (and act upon them), wrapping that call in a catch-all exception handler.

The command line processing function itself will invoke an appropriate function according to the command line arguments, and thus becomes an elaborate switch statement.

Complex functions are difficult to read and maintain, but can be simplified by separating the code into a series of function calls, such that each function's name essentially describes what it does. Thus programs become self-documenting.

In C++, classes would be useless without functions (or methods as they are known).