how does int main and void main work

Question

I am a beginner in C language  Can anyone explain in detail using example how main   int main    void main    main void   void main void   int main void  work in C language   As in what is happeneing when we use void main   and what is happening when i use int main   in simple language and so on  I know but cant understand what is it doing    main   - function has no arguments int main   - function returns int value void main   - function returns nothing etc    when i write simple hello world using the int main   return 0 it still gives me the same output as when using void main    so how does it work  What is its application

User · Answer

If you really want to understand ANSI C 89, I need to correct you in one thing; In ANSI C 89 the difference between the following functions:

int main()
int main(void)
int main(int argc, char* argv[])

is:

int main()

a function that expects unknown number of arguments of unknown types. Returns an integer representing the application software status.

int main(void)

a function that expects no arguments. Returns an integer representing the application software status.

int main(int argc, char * argv[])

a function that expects argc number of arguments and argv[] arguments. Returns an integer representing the application software status.

About when using each of the functions

int main(void)

you need to use this function when your program needs no initial parameters to run/ load (parameters received from the OS - out of the program it self).

int main(int argc, char * argv[])

you need to use this function when your program needs initial parameters to load (parameters received from the OS - out of the program it self).

About void main()

In ANSI C 89, when using void main and compiling the project AS -ansi -pedantic (in Ubuntu, e.g) you will receive a warning indicating that your main function is of type void and not of type int, but you will be able to run the project. Most C developers tend to use int main() on all of its variants, though void main() will also compile.

User · Answer

Neither main   or void main   are standard C   The former is allowed as it has an implicit int return value  making it the same as int main     The purpose of main s return value is to return an exit status to the operating system     In standard C  the only valid signatures for main are   int main void    and   int main int argc  char   argv    The form you re using  int main   is an old style declaration that indicates main takes an unspecified number of arguments   Don t use it - choose one of those above

[c] how does int main() and void main() work

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