lang/C/the.ansi.c.programming.language/notes.accompany.ansi.c/sx5k.html

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   9 <title>section 2.11: Conditional Expressions</title>
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  15 <H2>section 2.11: Conditional Expressions</H2>
  16
  17 <p>``Ternary'' is a ten-dollar word meaning ``having three operands.''
  18 (It's analogous to the terms unary and binary,
  19 which refer to operators having one and two operands,
  20 respectively.)
  21 The conditional operator is a bit of a frill,
  22 and it's a bit obscure,
  23
  24 so you may skip section 2.11 in the book on first reading,
  25 but please read the comments in these notes just below
  26 (under the mention of ``annoying compulsion'').
  27 </p><p>page 52
  28 </p><p>To see what the <TT>?:</TT> operator has bought us,
  29 here is what the array-printing loop might look like without it:
  30 <pre>   for(i = 0; i &lt; n; i++) {
  31                 printf("%6d", a[i]);
  32                 if(i%10==9 || i==n-1)
  33                         printf("\n");
  34                 else    printf(" ");
  35         }
  36 </pre></p><p>You may be finding this compulsion to write ``compact'' or
  37 ``concise'' code using operators like <TT>++</TT> and <TT>+=</TT> and
  38 <TT>?:</TT> a bit annoying.
  39 There are three things to know:
  40 <OL><li>In complicated code,
  41 these operators allow an economy of expression
  42 which <em>is</em> beneficial.
  43 Mathematicians are constantly inventing new notations,
  44 in which one letter or symbol
  45 stands for a complicated expression or operation,
  46 in order to solve complicated problems
  47 without drowning in so much verbiage
  48 that it would be impossible to follow an argument or check for errors.
  49 Computer programs are large and complex,
  50 so well-chosen abbreviations can make them easier to work with, too.
  51 <li>Some C programmers, it's true,
  52 do take the urge to write succinct or concise code to excess,
  53 and end up with cryptic, bewildering, obfuscated, impenetrable messes.
  54 (I'm not apologizing for them:
  55 I hate
  56 overly abbreviated,
  57 impossible-to-read
  58 code, too!)
  59 <li>Since there is overly concise C code out there,
  60 it's occasionally necessary to dissect a piece of it and figure
  61 out what it does,
  62 so you need to have enough familiarity with these operators,
  63 and with some standard, idiomatic ways in which they're
  64 commonly combined,
  65 so that you won't be utterly stymied.
  66 </OL>However,
  67 there is <em>nothing</em> that says that you
  68 have
  69 to write concise code yourself.
  70 Don't be lured into thinking
  71 that you're not a ``real C programmer''
  72 until you routinely and easily write code which no one else can read.
  73 Write in a style that's comfortable to you;
  74 don't be embarrassed if your code seems ``simple.''
  75 (Actually, the very best code seems simple, too.)
  76 With time,
  77 you'll probably come to appreciate at least some of the idioms,
  78 and to be comfortable enough with them
  79 that you may want to use a few of them yourself,
  80 after all.
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