Re: undefined sqrt()

[Karthik Vishwanath <karthik@northstar.dartmouth.edu>]

Try:

gcc -Wall -lm -o glide glide.c

-K

----------------------------------------
The biggest difference between time and space is that you 
can't reuse time -- Merrick Furst


On Thu, 24 Oct 2002, Theo. Sean Schulze wrote:

> Hello,
> 
> This is a real newbie type question.  Usually my problems with C involve pointers, but this one is a problem with the function sqrt().  I had a math problem I needed to solve, and having forgotten my high school algebra about 25 years ago, I thought I could quickly write a C program to get an approximate answer by brute force.  This program is supposed to figure out one of the sides of a right triangle using the other side and the hypotenuse.  The hypotenuse has a fixed relationship to the side of unknown lenght.  Anyway, here is the code, such as it is:
> 
> 
> //
> // Filename: glide.c
> // Version: 0.0.1     Date: 24 October, 2002
> //
> // Author: T. Sean Schulze
> // System: i386-slackware-linux-gnu
> //
> // Purpose: The purpose of this script is to use brute force to find out
> // how long the long side and the hypotenuse of a right triangle are 
> // when the short side of the triangle is 35 feet long.  This will, of 
> // course, vary depending on the angle between the two unknown sides.
> //
> // Limitations: Down and dirty.  Not useful for much else than this brute
> // attempt.
> 
> #include <stdio.h>
> #include <math.h>
> #include <float.h>
> #include <stdarg.h>
> #include <stddef.h>
> #include <stdlib.h>
> #include <unistd.h>
> #include <errno.h>
> 
> double a ;
> double b ;
> double c ;
> double GLIDE ;
> 
> int
> main(void) /*(int argc, char **argv)*/
> {
> 	GLIDE = 0.012 ;
> 	a = 0.0 ;
> 
> 	while( b < 35.0 ) 
> 	{
> 		a++ ;
> 		c = a * (1 + GLIDE) ;
> 		b = sqrt((c * c) - (a * a)) ;
> 
> 	}
> 	
> 	printf("Glide = %f\n", GLIDE);
> 	printf("a = %f\n", a) ;
> 	printf("b = %f\n", b) ;
> 	printf("c = %f\n", c) ;
> 
> 	exit(0);
> 
> }
> 
> When I try to compile it, I get these messages:
> 
> dragoon:/home/tschulze/bin # gcc -Wall -o glide glide.c
> /tmp/ccXahjXY.o: In function `main':
> /tmp/ccXahjXY.o(.text+0x98): undefined reference to `sqrt'
> collect2: ld returned 1 exit status
> 
> Could someone please give me a hint why this doesn't work?
> 
> TIA,
> Sean
> 
> -- 
> Theo. Sean Schulze
> tschulze@teamfinders.org
> -
> To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>