" 'void main() ' vs 'int main()' " and " 'getch();' vs 'return.0' "

[fallen_warrior]

i've seen both, but only used void main() and getch(); as that has been all my high school has ever taught me. Is there any difference in the two? (i'm using borland 5.02 btw)....

[MoMad]

if you know about functions, you will know that main is just another function... so:

void main(void) - is a function that returns nothing and takes in nothing.
int main(void) - is a function that returns an int and takes in nothing.
int main(char*,int) - is a function that returns an int and takes in a pointer to a char and an int

getch() - is only borland specific.

all it does is wait for a user to press <enter>

[MoMad]

return 0 just exists the program if u start the program with an int return type...

[Vlatko]

You should use main in this form

main( int argc, char *argv[ ], char *envp[ ] )
{
program-statements
}

[amac]

getch() - is only borland specific.

getch() is not borland specific... Its available where ever it is defined...

You can use it in VC++ by including conio.h or on pretty much any UNIX machine by including... curses.h or ncurses.h

all it does is wait for a user to press <enter>

Actually it retrieves a character from standard input (STDIN) without echo'ing it... although waiting for user to press enter is one use of it.

[Zaei]

Use return 0 if it is at all possible. Sometimes the program will quit if you just return 0, so getchar() (the stdio version of getch()) is required. If it was me, I would probably hurt anyone who put that at the end of a program.

Z.

[CornedBee]

char* envp[] as argument to main is microsoft specific.
and the totally ansi version of main is:
int main (int argc, char* argv[]);

[MoMad]

Originally posted by CornedBee
char* envp[] as argument to main is microsoft specific.
and the totally ansi version of main is:
int main (int argc, char* argv[]);

it doesnt matter what the variable name is.

[parksie]

Actually...there's a very good reason why you should not use void main(...).

On Intel/Win32, return values from functions are normally passed through EAX (the register). So therefore, if you don't return a value it's not really a problem.

However, some systems return values on the stack, so if you haven't pushed a value, then it'll all be out of sync and gets very messy indeed.

Moral of the story, do what ANSI and ISO tell you to do

[CornedBee]

the variable name does not matter, but no system/compiler combo except win32/vc++ will fill anything into the third argument

[MoMad]

aah I see. thx