Assuming you mean in C++:
and the input/output:
int main(int argc, char*argv)
for(register short int i=0;i<argc;i++)
as you can probably see, int argc holds how many command line arguments are sent (seperated by spaces). char*argv holds the actual arguments as character arrays
jshao@MCP ~/Programming/C++ $ ./test.exe a b c d
if your program was called on the command line, there's always at least one argument (argc>=1) and the first argument is always the title of the program/way it was invoked (argv="./test.exe").