langs a-z

Task/Greatest-common-divisor/UNIX-Shell/greatest-common-divisor-1.sh

@@ -0,0 +1,14 @@
+gcd() {
+	# Calculate $1 % $2 until $2 becomes zero.
+	until test 0 -eq "$2"; do
+		# Parallel assignment: set -- 1 2
+		set -- "$2" "`expr "$1" % "$2"`"
+	done
+
+	# Echo absolute value of $1.
+	test 0 -gt "$1" && set -- "`expr 0 - "$1"`"
+	echo "$1"
+}
+
+gcd -47376 87843
+# => 987

Task/Greatest-common-divisor/UNIX-Shell/greatest-common-divisor-2.sh

@@ -0,0 +1,15 @@
+alias gcd eval \''set gcd_args=( \!*:q )	\\
+	@ gcd_u=$gcd_args[2]			\\
+	@ gcd_v=$gcd_args[3]			\\
+	while ( $gcd_v != 0 )			\\
+		@ gcd_t = $gcd_u % $gcd_v	\\
+		@ gcd_u = $gcd_v		\\
+		@ gcd_v = $gcd_t		\\
+	end					\\
+	if ( $gcd_u < 0 ) @ gcd_u = - $gcd_u	\\
+	@ $gcd_args[1]=$gcd_u			\\
+'\'
+
+gcd result -47376 87843
+echo $result
+# => 987