Anyone knows log function??

[bread19]

Hello..guys..
Thank u for the answer for previous question..

Now..I got new question for log function..

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

int main(int argc, char *argv)
{
    int n;
    ...
    ...
    Print_Round(n);
    ...
    ...
}

Print_Round(int k)
{
    int j=1;
    while ( j < (log10(k)/log10(2)) {
         printf("Round is %d\n",j);
    }
}

I wrote code like that..but there is error when I compile..
I got those message..

/var/tmp/ccSHNicS.o: In function `Print_Round':
/var/tmp/ccSHNicS.o(.text+0x1f0): undefined reference to `log10'
/var/tmp/ccSHNicS.o(.text+0x20f): undefined reference to `log10'
collect2: ld returned 1 exit status

anybody help me out why the error occurs??

[quzah]

Your compiler doesn't have a 'log10' function apparently. 'log10' isn't an ANSI standard function according to this info on log10. Any function which isn't part of the ANSI standard is only around if your compiler has implemented it. IE: Not ANSI = may not be included.

Quzah.

[swoopy]

It appears you are getting an error during the link phase. You may have to link in the math library. Someone who's familiar with linux/unix may know. Maybe some switch like: -l math

[Shiro]

The logarithm functions are part of the C standardlibrary and when using them, you need to include math.h. Here are a few of the logarithm functions as stated in the standard.

7.12.6.7 The log functions

Synopsis
1 #include <math.h>
double log(double x);
float logf(float x);
long double logl(long double x);

Description
2 The log functions compute the base-e (natural) logarithm of x. A domain error occurs if the argument is negative. A range error may occur if the argument is zero.

Returns
3 The log functions return loge x.

>collect2: ld returned 1 exit status

Here ld is the linker, according to the error messages, the function log10 cannot be found. Probably you have forgotten to link a required library with the program or the path-settings are wrong.