command line arguments

[Geminias]

hi friends,

how would i be able to accept command line arguments for a program?

So if i had a program called: ROT13 and i wanted to decrypt a certain code i could just type: ROT13 -<certain code> and it would decrypt it for me and display it on screen.

[wtd]

What do you think the arguments to "main" are for?

code:

int main(int argc, char ** argv)

[Geminias]

for anyone else whose interested in knowing:

code:

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

"argc" is automatically determined by how many spaces you use.
argv is a pointer to character array.


so if you typed: "myprog.exe argument1 argument2"
argc = 2, because there were two spaces.
argv[0] = name of program "myprog.exe"
argv[1] = argument1
argv[2] = argument2


big thanks to wtd for his guidance. Also:

Quote:

int main(int argc, char ** argv)

does the "**" mean "const char * argv"?[/quote]

[wtd]

No, ** mean pointer to pointer. A C-style (as opposed to C++ style) string is an array of characters terminated by the null character. An array in C and C++ is just a glorified pointer. Thus an array of C-style string is an array or arrays of characters.

Or... a pointer to a pointer to a character.

[wtd]

Also, if you provide two arguments to a program, argc is 3, since there are three strings in the array.

[Geminias]

c++:

int main (int argc, char ** argv) {      std::cout << * argv;      return 0; }

all i seem to be able to get is an address when i use a glorified pointer.

[wtd]

When I compile and run that (after adding the include for iostream), I get:

code:

C:\>g++ args.cpp C:\>a a

[Geminias]

ok for some reason i'm getting it now. wierd, before it was only giving me an address.