Programming

Thanks Don!
So that 1$ as the first argv, here width; 2$ as 2nd argv as 1, 3rd -> 2, 4th->3 and 5th->4. The order of the argv was switched on purpose for the 3rd printf in main() function.
On my system (Ubuntu 13.10), the second style does not print the leading 0s between 1 and 2, that does not matter to me.
Anyway, How can I, or how long will it take to, get all those tricks?!

You're digging deeper into printf than most people bother to... You're teaching me new stuff too now

Don Cragun :

Your explanation was awesome, and it's crystal clear as always, actually when I was in college even our lecturers didn't teach/explain us any programming language / any single statement in depth as clear as you guys here teaching us.

I have noticed in many threads in forum especially You, Corona, Scrutinizer and RudiC explained so clearly that even beginner who just knows alphabets would be able to create sentence.

Thanks you so much for your valuable time.

As I always say Unix.com is well organized, and got prompt support compare any forum which one can search in any search engine.

Regards,
Akshay

Yes, you have it.

Please, stop calling them tricks! I haven't used any tricks in any of the code I've shown you. (I know some tricks that I could use because I have seen (and written) some of the code that implements various utilities, library routines, and kernel features. But, tricks can disappear or start working differently at any time.) Everything I have used in the examples I've shown you are features documented in the man pages. I know that some implementations take greater care in producing quality man pages than some other implementations, but a good set of man pages (or a copy of the C Standard or the POSIX Standard) is your usually your best reference as long as you can figure out which man page to look for. In the old days, the manuals were available as printed documents and you could read them from cover to cover to get an idea of what was available even if you didn't need it at that time. (Just reading the table of contents gives you more information than you might think.) I reread the (currently 3,906 page) POSIX standard every time it is revised (every 5 to 10 years). There is a bunch of stuff in there I have never needed to use, a bunch of stuff I seldom use, and a bunch of stuff I use every day. After you've read a few dozen man pages, you may get to a point where you notice the symmetry between interfaces and you develop a feel for how things are supposed to work. Ken and Dennis had a great plan when they designed and built their first UNIX System. There has been a lot of unnecessary bloat added to UNIX and Linux systems since then, but the simple, basic principles are still hidden in those manuals.

Enjoy learning. It is a lifelong process!

The stuff you're getting into here isn't stuff that I use regularly. I reread the man pages and played around with code to try to create an example that would help you understand what the words on the man page meant. (And, as you may have noticed, I got something to work on my laptop that didn't use the format specified by the standards. That may have been why it didn't work on Ubuntu. In case you didn't notice, my original posting had the 0 fill flag in the wrong place. My original example had:

Code:

                printf("%2$*1$d%03$*1$d%4$*1$d%5$*1$d\n",
                        width, 1, 2, 3, 4);
                printf("%4$*1$d%05$*1$d%2$*1$d%3$*1$d\n\n",
                        width, 3, 4, 1, 2);

but has been fixed in message #7 in this thread to follow the form specified by the standards:

Code:

                printf("%2$*1$d%3$0*1$d%4$*1$d%5$*1$d\n",
                        width, 1, 2, 3, 4);
                printf("%4$*1$d%5$0*1$d%2$*1$d%3$*1$d\n\n",
                        width, 3, 4, 1, 2);

Both happen to work on OS X, but the standards specify that flags are supposed to follow the n$ that specifies which argument is to be processed and before the optional minimum field width, precision, and length modifiers, and the mandatory conversion specifier character. If you used the original form and it didn't work on Ubuntu, you may want to try using the corrected format strings.)