Why does this not work?

[Tobi G. via Digitalmars-d-learn]

On Friday, 1 January 2016 at 14:00:41 UTC, TheDGuy wrote:
>     writeln("Which number should i guess?");
> 	string input = readln();
> 	int i = to!int(input);

The solution is that readln() returns a string that also contains 
the newline
this can be solved by easily stripping the newline off

import std.string;

int i = to!int(input.strip);