Test

cachematrix.R

@@ -4,12 +4,40 @@
 ## Write a short comment describing this function
 
 makeCacheMatrix <- function(x = matrix()) {
-
+  inv <- NULL
+
+  set <- function(y) {
+    x <<- y
+    inv <<- NULL
+  }
+
+  get <- function() x
+
+  setinverse <- function(inverse) inv <<- inverse
+
+  getinverse <- function() inv
+
+  list(set = set, 
+       get = get,
+       setinverse = setinverse,
+       getinverse = getinverse)
 }
 
 
 ## Write a short comment describing this function
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+  inv <- x$getinverse()
+
+  # if cached inverse exists, return it
+  if(!is.null(inv)) {
+    message("getting cached data")
+    return(inv)
+  }
+
+  # otherwise calculate the inverse
+  data <- x$get()
+  inv <- solve(data, ...)
+  x$setinverse(inv)
+  inv
 }