* in command line causes havoc

when a * is inputted as one of the arguments in a command line call odd things happen. this is from a command line version of a polish calculator (one of the k&r exercises) :

./a.out 1 2 - 4 5 + -
results in:
-10

./a.out 1 2 - 4 5 + *
results in:
error: unknown command a
error: unknown command o
error: unknown command t
error: unknown command c
error: unknown command l
9

one previous not-working version of this code, outputted (that means was part of argv) everyone of the file names in my current directory when * was one of the command line arguments.

why should the * play such havoc? i get the feeling it must be something to do with the environement? that the * as one of the command line arguments is designed to do something i don't know about maybe?

i know it's a wildcard and therefore symbolises 'everything' on it's own but why should this effect anything in my particular situation?

It looks like the * is indeed being expanded to a file-list. It will need to be quoted to tell the shell to leave it alone.

Try:
./a.out 1 2 - 4 5 + \*

yup, you're right. that got it. thanks.