8 replies to this topic

[Esi_Gold]

Dear Guys,
I just wrote a simple program to calculate Square root of a number, But when I try to compile it, I get this Error :

/tmp/ccmo2eCt.o: In function `main':

test01.c:(.text+0x59): undefined reference to `sqrt'

collect2: ld returned 1 exit status

Tha's the source Code :

/* Test1 : Test1.c 

   This program calculate root of the numbers */

#include <stdio.h>

#include <math.h>


int main()


{


   int c1;

   printf( "Enter your number\n" );

   scanf( "%d", &c1 );

   printf( "%.2f", sqrt( c1 ) );


return 0;

}

Could anybody help me?

[John]

When you are compiling, you need to link the math library:

Quote

cc test.c -o test.o -lm

Adding the -lm should fix your problem.

[v0id]

Do like John suggested, and if you're not using GCC, you can check your compiler manual for information on how to link with libraries.

[Sree]

I hav run the same prog but not getting any errors.But I think it 'll bw solved if u declear a int variable seperately & assign the sqrt in it and write.But still interestec to know the cause of the problem.

[mholt]

Regarding above: If you save the value returned by sqrt then save it to an int, you'll truncate it, meaning you'll lose precision and likely round down, which may not be what you intend...

[John]

Sree said:

I hav run the same prog but not getting any errors.But I think it 'll bw solved if u declear a int variable seperately & assign the sqrt in it and write.But still interestec to know the cause of the problem.

If you compiled it using an IDE, you won't reproduce the error because the IDE will link the math library automatically. However, if you try compiling the code above without the -lm, via the console, you should reproduce the error. At least I did...

[Xav]

Sree said:

I hav run the same prog but not getting any errors.But I think it 'll bw solved if u declear a int variable seperately & assign the sqrt in it and write.But still interestec to know the cause of the problem.

If you declare an integer variable and assign the sqrt() value to it, it shouldn't make any difference than if you embed the function call within the output method. sqrt() returns a numeric value, so if you concatenate it within the output string directly, it should work in the same way. It does make it slightly harder to debug, though, as you can't tell whether the sqrt() call or the output call has generated the error.

[Esi_Gold]

Dear Guys, I compiled the source code using -lm , It worked perfect!
Thanks all

Edited by Esi_Gold, 05 May 2008 - 06:15 AM.

[Xav]

No probs. :)
I love the green font, by the way...