/*-------------------------------------------------------------------
  xcenter(x,length,pad)
   returns string center to length with pad
   If length = 0 then string is center within existing length
   If pad = "" then pad = " "
   Mark McDonald 2008
  -------------------------------------------------------------------*/
char *xcenter(char *x, int xn, char*xpad){
  char *xret = "";
  int xlen;
  int xdif;
  int xleftn;
  int xrightn;
  if(xn == 0){xn = strlen(x);}
  strstripleading(x, " ");
  strstriptrailing(x, " ");
  xlen = strlen(x);
  xdif = xn - xlen;
  xleftn = xdif / 2;
  xrightn = xdif - xleftn;
  xret = strcompose(strgenstr(xpad, xleftn), x, strgenstr(xpad,xrightn);
return(xret);
}//xcenter