What is the advantage of using functions and write a c program to explain about built-in functions with examples?

Answer 1

C does not have any built-in functions as such. The language allows the programmer to create functions or to include functions contained in external function libraries, but the language itself has no functions whatsoever. The C standard library is not considered built-in since programmers are free to ignore the standard library completely. However, the library contains highly efficient, optimised functions that are considered "general purpose" and therefore useful to the majority of programmers. The programmer can use these functions as the basis for more complex, more specialised functions.

The main advantage of functions is that they allow programmers to break programs down into a series of simple subroutines, each of which is handled by a function. Functions can call other functions, including themselves, and can be called as often as required. Although some code duplication is inevitable in any program, by placing duplicate code in a function, the programmer ensures that the code remains consistent. Since the function code is in one place, it is much easier to maintain that code, there is no need to make multiple changes across all duplicates, which is error prone and could introduce inconsistencies. Also, with well-named functions, code becomes self-documenting, making it easier to express ideas in code without the need for verbose comments within the code itself, which tends to be distracting rather than helpful.