Programming

I have to files
File1

1 23
2 34
3 7
4 56
5 61
6 22
7 65

File2

2 21
4 32
7 22

Now i need to compare column1 of both the files and generate a third file which should contain all the values of 1st column of 1st file and in the second column i need to get the coressponding row vaues of the second file.and other values to be zero.

Output shuld be like this:

1 0
2 21
3 0
4 32
5 0
6 0
7 22

Code:

awk 'FILENAME=="file1" {arr[$1]=$2}
       FILENAME=="file2" { print $1, ($1 in arr) ? arr[$1] : "0"; } ' file1 file2 > newfile

try this

BUT i need to compare more than one file..around thousands....so need to compare one file with thousand files...