implement functions and add comments

Author: natemoser

cachematrix.R

@@ -6,14 +6,39 @@
 ## same input matrix, the cached result will be returned, rather than the
 ## inverse being calculated again.
 
+## makeCacheMatrix: accepts a matrix as input, and returns
+## an object with functions for getting and setting the cached matrix, as
+## well as getting and calculating/setting the inverse matrix.
 
 makeCacheMatrix <- function(x = matrix()) {
-
+    m <- NULL
+    set <- function(y) {
+        x <<- y
+        m <<- NULL
+    }
+    get <- function() x
+    setinverse <- function(inverse) m <<- inverse
+    getinverse <- function() m
+    list(set = set, get = get,
+         setinverse = setinverse,
+         getinverse = getinverse)
 }
 
 
-## Write a short comment describing this function
+## cacheSolve: accepts an object that was created via makeCacheMatrix, and 
+## if the inverse of the matrix has previously calculated, returns that
+## cached result. Otherwise, the inverse of the matrix is calcuated, stored
+## in the object passed in to cacheSolve, and then the inverse matrix is 
+## returned.
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    m <- x$getinverse()
+    if(!is.null(m)) {
+        message("getting cached data")
+        return(m)
+    }
+    data <- x$get()
+    m <- solve(data, ...)
+    x$setinverse(m)
+    m
 }