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   9 <title>section 3.4: Switch</title>
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  15 <H2>section 3.4: Switch</H2>
  16
  17 pages 58-59
  18 <p>We won't be concentrating on <TT>switch</TT> statements much
  19 (they're a bit of a luxury;
  20 there's nothing you can do with a <TT>switch</TT>
  21 that you can't do with an <TT>if</TT>/<TT>else</TT> chain,
  22 as in section 3.3 on page 57).
  23 But they're quite handy,
  24 and good to know about.
  25 </p><p>The example on page 59 is about as contrived as the example in
  26 section 1.6
  27 (page 22)
  28 which it replaces,
  29 but studying both examples will give you an excellent feel for
  30 how a <TT>switch</TT> statement works,
  31 what the <TT>if</TT>/<TT>then</TT> statements are
  32 that a <TT>switch</TT> is equivalent to
  33 and how to map between the two,
  34 and why a switch statement can be convenient.
  35 </p><p>In the example
  36 in the text,
  37 note especially the way that ten <TT>case</TT> labels are
  38 attached to one set of statements
  39 (<TT>ndigit[c-'0']++;</TT>).
  40 As the authors point out,
  41 this works because of the way switch cases ``fall through,''
  42 which is a mixed blessing.
  43 </p><p>The danger of fall-through is illustrated by:
  44 <pre>   switch(food) {
  45                 case APPLE:
  46                         printf("apple\n");
  47 <br>
  48 <br>
  49                 case ORANGE:
  50                         printf("orange\n");
  51                         break;
  52 <br>
  53 <br>
  54                 default:
  55                         printf("other\n");
  56         }
  57 </pre>When <TT>food</TT> is <TT>APPLE</TT>,
  58 this code erroneously prints
  59 <pre>   apple
  60         orange
  61 </pre>because the <TT>break</TT> statement after the <TT>APPLE</TT> case was omitted.
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  71 This page by <a href="http://www.eskimo.com/~scs/">Steve Summit</a>
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