Erlang读stdin写stdout [英] Erlang read stdin write stdout

问题描述

我正在尝试通过 interviewstreet 学习erlang。我只是现在学习语言，所以几乎什么都不知道。我想知道如何从stdin读取并写入stdout。

I'm trying to learn erlang through interviewstreet. I just learning the language now so I know almost nothing. I was wondering how to read from stdin and write to stdout.

我想编写一个写Hello World！的简单程序。在stdin中收到的次数。

I want to write a simple program which writes "Hello World!" the number of times received in stdin.

所以用stdin输入：

So with stdin input:

6

写入stdout：

Hello World!
Hello World!
Hello World!
Hello World!
Hello World!
Hello World!

理想情况下，我会一次阅读stdin一行（尽管在这种情况下只是一位数） ）所以我想我将使用get_line。

Ideally I will read the stdin one line at a time (even though it's just one digit in this case) so I think I will be using get_line. That's all I know for now.

谢谢

谢谢

推荐答案

这是另一个解决方案，也许更有用。

Here's another solution, maybe more functional.

#!/usr/bin/env escript

main(_) ->
    %% Directly reads the number of hellos as a decimal
    {ok, [X]} = io:fread("How many Hellos?> ", "~d"),
    %% Write X hellos
    hello(X).

%% Do nothing when there is no hello to write
hello(N) when N =< 0 -> ok;
%% Else, write a 'Hello World!', and then write (n-1) hellos
hello(N) ->
   io:fwrite("Hello World!~n"),
   hello(N - 1).

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