I am running a script.

if in between due to any problem it fails I have to creat a error log file mentioning what was the error with date and time.

If script executed succesfully I have to create success log file.

Can u help me out. its urgent

You could do something like this:

if something was successful
then
      echo "$(date): successfully did something" > /tmp/success.log
else
      echo "$(date): something failed " > /tmp/error.log
      exit 1
fi

Actually if something is competently written, its exit code should indicate whether or not it was successful; then you simply write

if something; then
  date +"%c: successfully did something"
else
  date +"%c: something failed"
fi >>/tmp/error.log