Invalid Page Faults with Command Line Args

Hello. I was making a command line xor encryption tool (mainly for fun), and I did most of it pretty good. But when I compile it (without any errors or warnings), and then run it with the nessesary arguments, it throws a invalid page fault at me. :(

Well here is a snippet of the code (a bit large to post the entire thing...):

Code:

void fSyntax()
{
	cout << "\nThe correct syntax is: <filename> <password> [--decrypt]\n";
	exit(1);
}

int main(int argc, char *argv[])
{
	int i;
	if((argc < 2) || (argc > 3))
		fSyntax();
	while( i < argc )
	{
		if(!strcmp(argv[argc],"--decrypt"))
		{
			fstream FileD(argv[1], ios::in | ios::out | ios::nocreate);
			if(!FileD)
				exit(1);
			fDecrypt(FileD, argv[2]);
			FileD.close();
			exit(1);
		}
		i++;
	}
	fstream FileE(argv[1], ios::in | ios::out | ios::nocreate);
	if(!FileE)
		exit(1);
	fEncrypt(FileE, argv[2]);
	FileE.close();
	return 0;
}

Now what do I do? :p

I'm thinking it has something to do with the while() loop, but I can't be sure on that.

Well, thanks for your help.

if(!strcmp(argv[argc]
argv is an array that it argc elements long -- argv[0] to argv[argc-1].

argv[argc] is an out of bounds index.

>>argv[argc] is an out of bounds index.
In normal array terms it would be out of bounds, but for command line args, argv[argc] is a NULL pointer.

Aha, i fixed it.

Code:

int i;

was supposed to be

Code:

int i = 0;

Originally posted by Hammer
>>argv[argc] is an out of bounds index.
In normal array terms it would be out of bounds, but for command line args, argv[argc] is a NULL pointer.

Good catch, I forgot that one.

Originally posted by KneeLess
Aha, i fixed it.

Code:

int i;

was supposed to be

Code:

int i = 0;

... which is why a for loop would have been a better choice, imo. It makes mistakes like that easier to see.