undefined reference to static variable in c++

Suppose i have a code which need to reference static variable

so we have following code in trial.h

class Trial

{

static int v;

void setCode();

}

in trail.cc

#include "trial.h"

void Trial::setCode()

{

v=1;

}

This above code will give undefined reference to Trial::v error. To remove this error either remove static word from v in .h file or if it is necessary to have static word. then do as following.

in trial.cc

#include "trial.h"

int Trial::v;

void Trial::setCode()

{

v=1;

}

now your error is gone . happy coding