Basic example of creating a record and iterating over a list of elements.

first-steps-with-erlang.erl

-module(poc).
-export([all/0,say_hello/1]).

-record(person,{name,genre,age}).

new_person(Name, Genre, Age) ->
  #person{name=Name, genre=Genre, age=Age}.

isOlderThanAveragePeople(Age,AverageAge)->
  Age>=AverageAge.

say_hello(Person)->
  case Person#person.genre of
    "m" ->
      io:fwrite("Hello mister ~p , you're ~w and you are older than average people\n", [Person#person.name, Person#person.age]);
    "f" ->
      io:fwrite("Hello miss ~p , you're ~w and you are older than average people\n", [Person#person.name, Person#person.age])
  end.


all() ->
  John = new_person("John","m",33),
  David = new_person("David","m",18),
  Mick = new_person("Mick","m",42),
  Mariah = new_person("Mariah","f",51),
  Sarah = new_person("Sarah","f",11),
  People = [John,Mariah,David,Mick,Sarah],
  AverageAge = round(calculate_total_age(People) / length(People)),
  io:fwrite("The average age is ~w years old.\n",[AverageAge]),
  iterate(People,AverageAge).

iterate([Person],AverageAge) ->
  case isOlderThanAveragePeople(Person#person.age,AverageAge) of
    true -> say_hello(Person);
    _ ->ok
  end;

iterate([Person|People],AverageAge) ->
  case isOlderThanAveragePeople(Person#person.age,AverageAge) of
    true -> say_hello(Person);
    _ ->ok
  end,
  iterate(People,AverageAge);

iterate([],_) ->
  ok.

calculate_total_age([Person]) ->
  Person#person.age;


calculate_total_age([Person|People]) ->
  Person#person.age+calculate_total_age(People);

calculate_total_age([]) ->
  0.