enclose a line with quotation marks

Shell Programming and Scripting
1

i have a file like this

aaaa bbbb cccc
aaa aaaa
aa cccccccccccccccc
aaaaaaa aaaa aaaa

i want to enclose this lines with double quotation:

"aaaa bbbb cccc"
"aaa aaaa"
"aa cccccccccccccccc"
"aaaaaaa aaaa aaaa"

any idea? (preferably without using sed)
thanks in advance...

2 
sed -e "s/^/\"/g;s/$/\"/g" file

awk '{ printf "%s%s%s\n", "\"", $0, "\"" }' file
3 
awk ' sub(".*","\"&\"") ' file

or

sed "s/.*/\"&\"/" file
4

awk '{ printf "\"%s\"\n", $0 }' file