1 files changed, 24 insertions, 4 deletions
diff --git a/sum1.awk b/sum1.awk
index 8f1419b..9266789 100644
--- a/sum1.awk
+++ b/sum1.awk
@@ -5,15 +5,35 @@
 # output: sum of each column
 #   missing entries are treated as zeros
 
-BEGIN { OFS = FS }
 
-{
-    if (NF > nf_max)
-        nf_max = NF
+function isnum(n) {
+    sign = "[+-]?"
+    decimal = "[0-9]+[.]?[0-9]*"
+    fraction = "[.][0-9]+"
+    exponent = "([Ee]" sign "[0-9]+)?"
+    number = "^" sign "(" decimal "|" fraction ")" exponent "$"
+    return n ~ number
+}
+
+
+BEGIN {
+    OFS = FS
+}
+
+
+NR == 1 {
+    for (i=1; i<=NF; i++)
+        isnum($i) ? header[i] = "col" i : header[i] = $i
+}
+
+
+NF > 0 {
+    (NF > nf_max) ? nf_max = NF : nf_max = nf_max
     for (i=1; i<=NF; i++)
         sum[i] += $i
 }
 
+
 END {
     for (i=1; i<=nf_max; i++) {
         printf(OFMT, sum[i])