This text editor can add words, delete/undo, and redo operation
available actions
1->typing(inserting text, push undo stack)
2->undo(pop undo stack, push redo stack)
3->redo(pop redo stack, push undo stack)
4->Exit
Enter your desired action: 1
sentence is added!!!
text editor contains 3 words: [['testing'], ['is'], ['added']]
available actions
1->typing(inserting text, push undo stack)
2->undo(pop undo stack, push redo stack)
3->redo(pop redo stack, push undo stack)
4->Exit
Enter your desired action: 2
Undo action is performed!!!
text editor contains: [['testing'], ['is']]
available actions
1->typing(inserting text, push undo stack)
2->undo(pop undo stack, push redo stack)
3->redo(pop redo stack, push undo stack)
4->Exit