printf demo

bash-4.2$ echo 'Station Name
Station Code
A N %s DEV NAGAR
ACND
ABHAIPUR
AHA
ABOHAR
ABS
ABU ROAD
ABR' | awk 'NR%2==1 {printf $0","} NR%2==0 { print $0}'
Station Name,Station Code
awk: cmd. line:1: (FILENAME=- FNR=3) fatal: not enough arguments to satisfy format string
        `A N %s DEV NAGAR,'
             ^ ran out for this one