Counting numbers in other lines

[LewAlbert]

Why are you using find(':')? You know where ':' is. You have the number string, all you have to do is convert to a number and add them together. Is it the adding together that you are having a problem with?

I am going to read off a list of numbers and I need you to tell me the total. You do not have a pencil and paper to write the numbers down. How would you do that?

at the beginning of the program gives the "user" the ability to type in the name of the file that wants to read the search for the dot is to open this file without any extension errors.
The whole text file contains a lot of lines and I didn't know how to add numbers in different places of this file hence my question.