langs a-z

Task/Knuth-shuffle/UNIX-Shell/knuth-shuffle.sh

@@ -0,0 +1,22 @@
+# Shuffle array[@].
+function shuffle {
+	integer i j t
+
+	((i = ${#array[@]}))
+	while ((i > 1)); do
+		((j = RANDOM))                 # 0 <= j < 32768
+		((j < 32768 % i)) && continue  # no modulo bias
+		((j %= i))                     # 0 <= j < i
+
+		((i -= 1))
+		((t = array[i]))
+		((array[i] = array[j]))
+		((array[j] = t))
+	done
+}
+
+
+# Test program.
+set -A array 11 22 33 44 55 66 77 88 99 110
+shuffle
+echo "${array[@]}"