I am trying to calculate the correlation coefficient and prepare distance matrix and draw a plot of clustering. I am stuck in plotting. Here is my script:

   coef <- function(x,y){
   a <- sum(x * y) / sqrt(sum(x)^2 * sum(y)^2)
   return(a)
   }

   distance <- function(X) {
        n <- ncol(X)
        n <- nrow(X)
        distMat  <- matrix(0, nrow = n, ncol = n)

        for ( i in 1:(n-1) ) {
           for ( j in (i+1):n ) {
              v1 <- X[ , i]
              v2 <- X[ , j]
              d <- 1 - coef(v1, v2)
              distMat[i, j] <- d
              distMat[j, i] <- d
           }
        }

       for ( i in 1:n ) { distMat[i, i] <- 1 }

       hr <- hclust(distMat, method="average")  
       plot <- plot(hr)

       return(plot)
   }