horizontal tab - "\t" - what determines number of spaces?

When using the horizontal tab - "\t" - what determines number of spaces? - its not defined by ASCII is it?

If your program relies on the lenght of a string using "\t", is it not good to use "\t" b/c it varies from machine to machine?

Also, in a separate but related question, when using Visual C++, you can control how many spaces the "Tab" and "Indent" are. Is it good to use the Tab key to represent a number of spaces in a string literal? From what I can tell from Microsoft Help, the space inserted by the tab key is either converted to a number of spaces or converted to a tab character depending on the setting : Tools | Options | Tabs and you can either select "Insert Spaces" or "Keep Tabs"? Is that how this works?

if you need to space out your output, use fields, like this

printf("-10%s-10%s","hi", "hello");

that will left justify hi and hello in a field of 10. I think that is somethink that might help you.

thanks anyway,

I'm not using conversion specifications though.

chrismiceli, hes asking why are there x spaces in tab.

its probally a standard, but some programs cheat and use their own(whats worse is when they refuse to put in a '\t' and keep using ' '!).

>>what determines number of spaces?
The application doing the display.

A tab is a single byte, and simply represents an unspecified length of white space.

As for string literals etc, if you want control over the number of spaces, then output spaces, not tabs.

Tabs were used often when you wanted to easily output something to the console and line it up. Ie:

Code:

field	another	cprog	word
differ	final	they	line

To line these words up I just used a tab. (Cut and pasted from notepad)

Tabs usually (keyword: usually) go to the next column divisible by 8 (or the one right after that... i can't remember). So 8 letter words or bigger would disrupt tabbing. Which is why it isn't that popular to use tabs to create spaces.