Initialize an Array inside AWK Command and use the Array to Print using AWK - bash

Question

Im trying to Do a Comparison of 2 File Data and print certain out out of it.
My objective mainly here is to initlize an araay containing some values inside the same awk statement and use it for some printing purpose.
Below is the Command i am using which i feel looking like some syntactical error.
Please Help in the AWK part how I should define the Array also How i cna use it inside it.
Command tried -
paste -d "|" filedata.txt tabdata.txt | awk -F '|' '{array=("RE_LOG_ID" "FILE_RUN_ID" "FH_RECORDTYPE" "FILECATEGORY")}' '{c=NF/2;for(i=1;i<=c;i++)if($i!=$(i+c))printf "%s|%s|%s|%s\n",$1,${array[i]},$i,$(i+c)}'
SAMPLE INPUT FILE
filedata.txt
A|1|2|3
B|2|3|4
tabdata.txt
A|1|4|3
B|2|3|7
So my Output i am wanting is . -
A|FH_RECORDTYPE|2|4
B|FILECATEGORY|4|7
The Output Comprises the Differences -
PRIMARYKEY|COLUMNNAME|FILE1DATA|FILE2DATA
I want the Array to be initialized inside the AWK as array=("RE_LOG_ID" "FILE_RUN_ID" "FH_RECORDTYPE" "FILECATEGORY") and will correspond Column Names
The fetching columnname from the array- condition will be when ($i!=$(i+c)) whichever "i"th position mismatches i will print the "i" th Element from the Array.
Finding the Differences Section is working perfect if i remove the array part from my command, but my ask is i want to initialize an array containing the column names and print it too within the awk statement.
Just i need help how to incorporate the Array Part within AWK.

Answer 1

Unfortunately arrays in AWK cannot be assigned as you expect. As an alternative, you can use split function like:
split("RE_LOG_ID FILE_RUN_ID FH_RECORDTYPE FILECATEGORY", array, " ")
(Optional " " is needed because FS is overwritten.)
Then your command will look like:
paste -d "|" filedata.txt tabdata.txt | awk -F '|' '
BEGIN {split("RE_LOG_ID FILE_RUN_ID FH_RECORDTYPE FILECATEGORY", array, " ")}
{
c= NF/2;
for(i=1; i<=c; i++)
if ($i != $(i+c))
printf "%s|%s|%s|%s\n", $1, array[i], $i, $(i+c);
}'