Question

I am having problem with passing a pointer by reference.

This is the method

void set_range(double **measu)  
{   
if ((*measu)[0] < 0) //or i is used for a loop  
   return ;         
}


int main()
{
   double *mes;
   set_range(&mes[1]);

}

I have allocated memory and required values are set. But this program gives me “Unhandled exception Access violation reading location” error.
So my question is,how to pass the pointer of mes[1] instead of mes[0] (which normally passed when (&mes) is given) to the set_range method?

Answer 1

Change your function to take a double* instead of a double**, eg:

void set_range(double *measu)
{
  if (*measu < 0) //or i is used for a loop
    return;
}

int main()
{
  double *mes;
  ...
  set_range(&mes[1]);
}

Alternatively, use a real reference instead:

void set_range(double &measu)
{
  if (measu < 0) //or i is used for a loop
    return;
}

int main()
{
  double *mes;
  ...
  set_range(mes[1]);
}