Help with complex program

I am in need of a program. I am not sure how to program such a thing, so I'll ask for help. :p

1. I need to make this program calculate the total number of possible combinations of __letters__ and/or __numbers__ in an entered amount of digits. (example: entered 1 digit for numbers only and you get: 10. Enter two digits for numbers only and get: 100. ect.) There must be some sort of formula, but I am not sure what it is.

2. Is is possible with C++ to have this program make the mouse click at specified x,y and to have the program type in text and deleate text? If so, then how would I go about doing this? If no, then what language could accomplish this?