#' Updates the Hotelling Control Chart.
#' 
#' This function is used to update the phase II control chart with new
#' observations.
#' 
#' To use this function it is necessary to have the output given by the
#' function T2.2. At every step you should entry with the new data set.
#' 
#' @param datum2 The data set for the phase II. Shoul be a vector.
#' @param estat The values of the auxiliary statistics. Should be a list with a
#' vector with the mean of the mean vectors, a matrix with the average of the
#' variance-covariance matrices and a matrix with the means.
#' @param T2II A vector with the value of T2 statistic for one sample.
#' @param n The sample size. For individual observations, use n = 1.
#' @param j The index of the current sample.
#' @param m The number of samples in phase I. Only needed if the phase I data
#' set is show on the plot.
#' @return Add the new observation to the current Hoteliing control chart for
#' phase II.
#' @export
#' @author Daniela R. Recchia, Emanuel P. Barbosa
#' @seealso \link{T2.2}
#' @examples
#' 
#' mu <- c(5.682, 88.22)
#' Sigma <- symMatrix(c(3.770, -5.495, 13.53), 2)
#' datum <- data.1(20, 10, mu, Sigma)
#' estat <- stats(datum, 20, 10, 2)
#' datum2 <- data.2(estat, 10, p = 2)
#' T2II <- T2.2(datum2, estat, 10)
#' #Not showing the phase I data set.
#' cchart.T2.2(T2II, 20, 10, 1, 25, 2)
#' datum3 <- data.2(estat, 10, p = 2)
#' add.data(datum3, estat, T2II, 10, 2)
#' #Showing the phase I data set.
#' cchart.T2.2(T2II, 20, 10, 1, 25, 2, datum = datum)
#' datum3 <- data.2(estat, 10, p = 2)
#' add.data(datum3, estat, T2II, 10, 2, 20)
#' 
#' #Example with individual observations
#' datum <- data.1(50, 1, mu, Sigma)
#' estat <- stats(datum, 50, 1, 2)
#' datum2 <- data.2(estat, 1, p = 2)
#' T2II <- T2.2(datum2, estat, 1)
#' #Not showing the phase I data set.
#' cchart.T2.2(T2II, 50, 1, 1, 25, 2)
#' datum3 <- data.2(estat, 1, p = 2)
#' add.data(datum3, estat, T2II, 1, 2)
#' #Showing the phase I data set.
#' cchart.T2.2(T2II, 50, 1, 1, 25, 2, datum = datum)
#' datum3 <- data.2(estat, 1, p = 2)
#' add.data(datum3, estat, T2II, 1, 2, 50)
#' 
add.data <- function(datum2, estat, T2II, n, j, m = NULL)
{
    b <- T2.2(datum2, estat, n)
    if(is.null(m) == FALSE)
        j <- j + m + 1
    points(j, b[1], pch = 16)
    c <- c(j, j - 1)
    d <- c(b[1], T2II[1])
    lines(c, d)
    T2II <<- b
}