@q Define a macro so that the pound character can go in a URL.   @>
@q This should be in separate macro file and included here using @>
@q the TeX \input macro but it seems a shame to have a separate  @>
@q file for a single macro!                                      @>

{\catcode`\#=12 \gdef\POUND/{#}} % # in a URL

@* Introduction.
This is an adaptation of 
\pdfURL{Mike~Burn's~Sneaker~Program}{http://netgeek.ws/programs/sneaker/\POUND/c} 
using Knuth's \pdfURL{CWEB}{http://www-cs-staff.stanford.edu/\TILDE/knuth/cweb.html} tool
for ``literate programming''. For information on ``literate programming'' see
\pdfURL{Daniel~Mall's~website}{http://www.literateprogramming.com}. @q'@>

To produce a \CEE/ program file run the command {\tt ctangle} on this file.
To produce a \TeX\ file run the program {\tt cweave} on this file.
To \TeX\ this file run the program {\tt pdftex} on the \TeX\ file that was
output by {\tt cweave}.

@*2 Include the usual headers.

@c
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

@*2 Declare an array that lists the various sneaker colours.

@d SNEAKERS 7
@d LAST_SNEAKER 6

@c
static char *colours[SNEAKERS] = {"red","orange","yellow","green","blue","khaki","black"};

@* Main Program.
This program picks two random sneaker colours from the list in 
|colours| and outputs the result.

@c
int main (int argc, char **argv) {
  int sneaker_one;
  int sneaker_two;
  @<seed the random number generator@>;
  @<pick the colour of the first sneaker@>;
  @<pick the colour of the second sneaker@>;
  @<output the selected colours@>;
  return 0;
}

@*2 Pick the first colour.
Select a random number with a maximum value that is less than or equal
to the maximum number of colors in the list.

@<pick the colour of the first sneaker@>=
sneaker_one = rand() % LAST_SNEAKER;

@*2 Pick the second colour.
To get the second random number we will reduce
the maximum size of the random number by one. If we happen to get the 
value that was already chosen then |sneaker2| will be set to the value
|LAST_SNEAKER|.

@<pick the colour of the second sneaker@>=
sneaker_two = rand() % (LAST_SNEAKER - 1);
if (sneaker_two == sneaker_one) sneaker_two = LAST_SNEAKER;

@*2 Output the results.

@<output the selected colours@>=
printf("Sneakers %s, %s\n", colours[sneaker_one], colours[sneaker_two]);

@*2 Generate a new random number seed each time the program is run.
This is down by seeding the random number generator with the epoch
number returned by the time command.

@<seed the random number generator@>=
srand(time (0));