How to unzip files from folder in shell script (ksh)?

I have a folder (C:\shellprg\input\) containing .CSV, .zip, .gz files.
1] I want to find all .zip/.gz files from folder (C:\shellprg\input\).
2] unzip/uncompress files into the same folder (C:\shellprg\input\) through shell script.

I am using below commands for unzip files,

unzip <filename>
gzip -d <filename>

Could you please help me out. Thanks in advance.

cd /path/to/files
for i in *.gz
do
    gunzip $i
done
for i in *.zip
do
    unzip $i
done

Thanks for reply.
I want to write it in shell script. so i do not want to use cd command.

FILE=$PATH

How we can use FILE in for loop to do the same.