How to code in this situations

[paperdoll]

I want to make a program which switch letters.
like enigma.
ex) input a -> output 1) b 2)g 3)t.....

[gunnerfunner]

something like this?
http://www.cplusplus.com/forum/general/205209/

[paperdoll]

I think so. I'm beginner, started just few months ago ;(