Taking Full line for Caesar Encryption (c++)

Question

https://code.sololearn.com/c2eetK18J9GL/?ref=app

This is the code that I wrote, you know we can't get multiple inputs in seperate lines here so I wanted to get input by getline() func. but if I do this then I become not able to enter value for key variable.
(because, you know we need to add space after write something, i mean;
cin >> txt >> key;
Hello 3 <-- you see we added space )

anyways

Now, I want my program to take a full line as a text and a key.
If its possible to do HERE, plz tell me how to do?

Answer 1

https://code.sololearn.com/c2xa8r47FZ69/?ref=app