Ok, for me this was very difficult because I thought it would be much easier than that, I though that it was going to be very similar to a quiz that we did where we had to find the char o, so I used that quiz as a base.
But then I realize that I will need to find something that traduce the text from BanNana or baNNAna to banana so I found this blogs.
http://www.cplusplus.com/reference/cctype/tolower/
In the video the only difference is that he uses toupper.
Then I was stuck because I did not know what to do next to find the word banana, but then I find Fabrizzio Cortez blog who is a mechatronic engineer that did a very good job and uplouded high quality reviews. In the video I noticed that I must use .find which help us to find the word that we want, and also break to end the infinite loops.
In my code I wrote some notes: https://www.dropbox.com/s/be47iyu197epf64/wsq11.cpp?dl=0
PZ 