Just a smaller question from my previous post.

Well, if you read my other post, you know my predicament. The only thing I'm trying to figure out is how to code it where whenever the program sees a -1 it looks at the integers before it and depending on how many of each (like two 2's for example) outputs the correct letter, or in this case, b. i tried to use four integer variables and still unsure how many char variables I need also. The thing is you have to input the numbers to send out a basic 20 letter text message (spaces count as a letter also: 0 -1) using all the appropiate numbers and then hitting enter so it then produces the correct output. I don't know how to organize it where you can enter that huge string of numbers and it not having errors. I know to use sentinel controlled loop and possibly some while loops but I'm still not sure. Thanks.