[nivertech]

Erlang version (abc.erl):

    -module(abc).
    -export([main/0]).
    main() ->
        {ok,[A]} = io:fread("A=?","~f"),
        {ok,[B]} = io:fread("B=?","~f"),
        C = A + B,
        io:format("C=~f~n",[C]).

or

    -module(abc).
    -export([main/0]).
    main() ->
        {ok,[A,B]} = io:fread("A,B? ","~f ~f"),
        C = A + B,
        io:format("C=~f~n",[C]).

Compile and run from REPL:

    c(abc).
    abc:main().

Or just execute in REPL:

    {ok,[A]} = io:fread("A=?","~f").
    {ok,[B]} = io:fread("B=?","~f").
    C = A + B.
    io:format("C=~f~n",[C]).