Make this work better with a4 paper. Make the table of contents "hot" for PDF output. No additional packages are needed. Move code for \b@code, \e@code into the macros for the verbatim environment directly since they're not used elsewhere. Derive the name of the modules .idx from the jobname. Some clean ups.

/* hypot() replacement */

#include "config.h"
#include "myproto.h"
#include "mymath.h"

double hypot(x, y)
	double x;
	double y;
{
	double yx;

	x = fabs(x);
	y = fabs(y);
	if (x < y) {
		double temp = x;
		x = y;
		y = temp;
	}
	if (x == 0.)
		return 0.;
	else {
		yx = y/x;
		return x*sqrt(1.+yx*yx);
	}
}