#include <R.h>
#include <Rinternals.h>
#include <Rmath.h>

SEXP vecSum(SEXP Rvec){
  int i, n;
  double *vec, value = 0;
  vec = REAL(Rvec);
  n = length(Rvec);
  for (i = 0; i < n; i++) value += vec[i];
  printf("The value is: %4.6f \n", value);
  return R_NilValue;
}