@@ -0,0 +1,602 @@
+package seedu.address.logic.commands;%0A%0Aimport java.util.Stack;%0A%0Aimport seedu.address.model.task.Task;%0A%0A/** %0A * Undo previous add, delete and edit commands.%0A */%0Apublic class UndoCommand extends Command %7B%0A%0A    public static final String COMMAND_WORD = %22undo%22;%0A%0A    public static final String MESSAGE_USAGE = COMMAND_WORD;%0A%0A    public static final String MESSAGE_SUCCESS = %22Undo Command: %251$s%22;%0A%0A    private static Stack%3CCommand%3E PreviousCommands = new Stack%3CCommand%3E();%0A    %0A    %0A    @Override%0A    public CommandResult execute() %7B%0A        // TODO Auto-generated method stub%0A        return null;%0A    %7D%0A%0A%7D%0A

Add UndoCommand Class template