ex.8.4.c

// Function to calculate the absolute value of a number

#include <stdio.h>

float absoluteValue (float x)
{
	if ( x < 0 )
		x = -x;
	return (x);
}

// Function to compute the square root of a number

float squareRoot (float x)
{
	const float	epsilon	= .00001;
	float		guess	= 1.0;

	while ( absoluteValue (guess * guess - x) >= epsilon ) {
		guess = ( x / guess + guess ) / 2.0;
		printf ("guess = %f\n", guess);
	}

	return guess;
}

int main (void)
{
	printf ("squareRoot (2.0) = %f\n", squareRoot (2.0));
	printf ("squareRoot (144.0) = %f\n", squareRoot (144.0));
	printf ("squareRoot (17.5) = %f\n", squareRoot (17.5));

	return 0;
}