Re: Exercise 7-1

mdh <mdeh@comcast.netwrites:
[big snip]
>>
Ok, that looks reasonable, mostly. Your indentation is still
inconsistent, and I'd add braces to the while statements as well as the
if statements:
>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
>
int main(int argc, char *argv[])
{
int c;
if (strcmp(argv[0], "upper") == 0) {
while ((c = getchar()) != EOF) {
putchar(toupper(c));
}
}
else {
while ((c = getchar()) != EOF) {
putchar(tolower(c));
}
}
return 0;
}
>
But now I've lost track of what you were asking about.
>
One possible issue I can see is that argv[0], if it's non-null, points
to a string that "represents the program name". The manner in which
it does so may vary. For example, on a Unix-like system, it could be
any of "./upper", "/some/long/path/upper", or just "upper", depending
on how you invoked the program. I suggest printing the value of
argv[0] to see how it's actually being set. <OT>Try both installing
the program in some directory in your $PATH and invoking it by name,
and typing the full path to the executable file, and see what
happens.</OT>
>
For a simple test, you can just pick a way to invoke the program and
check for whatever value of argv[0] that gives you. For more
generality, you could figure out how to detect all the possible ways
it could be invoked.
>

On Wed, 2008-09-03 at 17:00 -0700, Keith Thompson wrote:

>
Probably he could use strstr() to check for "upper" or "lower" in
the program name that way, which would be reasonably portable.