add default input file

Author: pasit.r

src/reverse-words/index.js

@@ -1,5 +1,6 @@
 import reverseWords from './reverse-words.js'
+import path from 'path'
 
 const args = process.argv.slice(2)
-const filename = args[0]
+const filename = args[0] || path.resolve('./src/reverse-words/B-large-practice.in')
 reverseWords(filename)