Data commit

Task/Middle-three-digits/AWK/middle-three-digits.awk

@@ -0,0 +1,28 @@
+#!/bin/awk -f
+# use as: awk -f middle_three_digits.awk
+
+BEGIN {
+	n = split("123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1 -10 2002 -2002 0", arr)
+
+	for (i=1; i<=n; i++) {
+		if (arr[i] !~ /^-?[0-9]+$/) {
+			printf("%10s : invalid input: not a number\n", arr[i])
+			continue
+		}
+
+		num = arr[i]<0 ? -arr[i]:arr[i]
+		len = length(num)
+
+		if (len < 3) {
+			printf("%10s : invalid input: too few digits\n", arr[i])
+			continue
+		}
+
+		if (len % 2 == 0) {
+			printf("%10s : invalid input: even number of digits\n", arr[i])
+			continue
+		}
+
+		printf("%10s : %s\n", arr[i], substr(num, len/2, 3))
+	}
+}