add test case

subjects/printmiddle/README.md

@@ -0,0 +1,24 @@
+## print-middle
+
+### Instructions
+
+Write a program that prints the middle argument of the command line. 
+- If the number of arguments is less than 1, print (`'\n'`)
+- If the number of arguments is **even**, print the middle two arguments with a space (`' '`) between the arguments
+- If the number of arguments is **odd**, print the middle one.
+- Print (`'\n'`) at the end of the output.
+
+### Usage
+
+```console
+$ go run . | cat -e
+$
+$ go run . "Hello World!" | cat -e
+Hello World!$
+$ go run . "Hello World!" "World!" "All" | cat -e
+World!$
+$ go run . 1 2 3 4 | cat -e
+2 3$
+$ go run . "Hello" "World!" | cat -e 
+Hello World!$
+```