#include <stdio.h>
#include <math.h>
#include <string.h>
#include <errno.h>

#define PI	3.1415926535

int isnan(double);

int main(int argc, char *argv[])
{
	char *c;
	double x;
	double y;

	printf("ceil(7.28) = %f\n", ceil(7.28));
	printf("floor(7.28) = %f\n", floor(7.28));

	printf("fabs(3.14) = %f\n", fabs(3.14));
	printf("fabs(-3.14) = %f\n", fabs(-3.14));

	printf("log10(34) = %f\n", x = log10(34));
	printf("and back .. pow(10, %f) = %f\n", x, pow(10, x));

	printf("log(34) = %f\n", x = log(34));
	printf("and back .. exp(%f) = %f\n", x, exp(x));

	printf("fmod(8.2, 4.1) = %f\n", fmod(8.2, 4.1));
	printf("fmod(8.2, 4) = %f\n", fmod(8.2, 4));

	printf("modf breaks the integer and fraction up\n");
	x = modf(8.2, &y);
	printf("modf(8.2, &y) = %f, and y = %f\n", x, y);

	printf("sqrt(123) = %f\n", sqrt(123));


	printf("sin(pi/6) = %f\n", x = sin(PI/6));
	printf("asin(%f) = %f; 6 times it is %f\n", x, asin(x), 6 * asin(x));
	printf("cos(pi/6) = %f\n", x = cos(PI/6));
	printf("acos(%f) = %f; 6 times it is %f\n", x, acos(x), 6 * acos(x));
	printf("tan(pi/6) = %f\n", x = tan(PI/6));
	printf("atan(%f) = %f; 6 times it is %f\n", x, atan(x), 6 * atan(x));

	x = sqrt(-1.0);
	printf("sqrt(-1) = %f\n", x);
	if (isnan(x)){
		perror("sqrt");
	}
	c = strerror(errno);
	printf("The error message is \"%s\"\n", c);





	return(0);
}