The following...

import std.stdio;

void main() {
	write("How many students are there? ");
	int studentCount;
	readf("%s", &studentCount);
	write("How many teachers are there? ");
	int teacherCount;
	readf("%s", &teacherCount);

	writefln("Got it: there are %d students.", studentCount);
	writefln("And there are %d teachers.", teacherCount);
}


When given the input...
10
42

will produce the error... std.conv.ConvException@/usr/include/dlang/dmd/std/conv.d(2013): Unexpected '4' when converting from type LockingTextReader to type int

I understand what is wrong and how to fix it but the produced error is incorrect.

On Saturday, 9 May 2015 at 08:30:31 UTC, Dave Akers wrote:
> The following...
>
> import std.stdio;
>
> void main() {
> 	write("How many students are there? ");
> 	int studentCount;
> 	readf("%s", &studentCount);
> 	write("How many teachers are there? ");
> 	int teacherCount;
> 	readf("%s", &teacherCount);
>
> 	writefln("Got it: there are %d students.", studentCount);
> 	writefln("And there are %d teachers.", teacherCount);
> }
>
>
> When given the input...
> 10
> 42
>
> will produce the error...
> std.conv.ConvException@/usr/include/dlang/dmd/std/conv.d(2013):
> Unexpected '4' when converting from type LockingTextReader to type int
>
> I understand what is wrong and how to fix it but the produced error is
> incorrect.

To '\ n' does not remain in the input stream, it is necessary to write so:
-----
readf("%s ", &studentCount);

On Saturday, 9 May 2015 at 08:34:42 UTC, Dennis Ritchie wrote:
> On Saturday, 9 May 2015 at 08:30:31 UTC, Dave Akers wrote:
>> The following...
>>
>> import std.stdio;
>>
>> void main() {
>> 	write("How many students are there? ");
>> 	int studentCount;
>> 	readf("%s", &studentCount);
>> 	write("How many teachers are there? ");
>> 	int teacherCount;
>> 	readf("%s", &teacherCount);
>>
>> 	writefln("Got it: there are %d students.", studentCount);
>> 	writefln("And there are %d teachers.", teacherCount);
>> }
>>
>>
>> When given the input...
>> 10
>> 42
>>
>> will produce the error...
>> std.conv.ConvException@/usr/include/dlang/dmd/std/conv.d(2013):
>> Unexpected '4' when converting from type LockingTextReader to type int
>>
>> I understand what is wrong and how to fix it but the produced error is
>> incorrect.
>
> To '\ n' does not remain in the input stream, it is necessary to write so:
> -----
> readf("%s ", &studentCount);

I was meaning this as a bug report. But wanted to point out your
solution does not work. I was interested in D back in 1.0 days
but soo much has changed in d 2.0 that I'm reading through the
"Programming in D" book to learn all the new stuff and came
across this odd un-helpful error.
...
readf(" %s", &studentCount);
...
readf(" %s", &teacherCount);
...
that way it will ignore any non int chars left on the stdin
stream.

On Saturday, 9 May 2015 at 08:41:49 UTC, Dave Akers wrote:
> On Saturday, 9 May 2015 at 08:34:42 UTC, Dennis Ritchie wrote:
>> On Saturday, 9 May 2015 at 08:30:31 UTC, Dave Akers wrote:
>>> The following...
>>>
>>> import std.stdio;
>>>
>>> void main() {
>>> 	write("How many students are there? ");
>>> 	int studentCount;
>>> 	readf("%s", &studentCount);
>>> 	write("How many teachers are there? ");
>>> 	int teacherCount;
>>> 	readf("%s", &teacherCount);
>>>
>>> 	writefln("Got it: there are %d students.", studentCount);
>>> 	writefln("And there are %d teachers.", teacherCount);
>>> }
>>>
>>>
>>> When given the input...
>>> 10
>>> 42
>>>
>>> will produce the error...
>>> std.conv.ConvException@/usr/include/dlang/dmd/std/conv.d(2013):
>>> Unexpected '4' when converting from type LockingTextReader to type int
>>>
>>> I understand what is wrong and how to fix it but the produced error is
>>> incorrect.
>>
>> To '\ n' does not remain in the input stream, it is necessary to write so:
>> -----
>> readf("%s ", &studentCount);
>
> I was meaning this as a bug report.

issues.dlang.org please, otherwise no-one will remember to fix it.

On Sat, 09 May 2015 09:23:23 +0000, John Colvin wrote:

> On Saturday, 9 May 2015 at 08:41:49 UTC, Dave Akers wrote:
>> On Saturday, 9 May 2015 at 08:34:42 UTC, Dennis Ritchie wrote:
>>> On Saturday, 9 May 2015 at 08:30:31 UTC, Dave Akers wrote:
>>>> The following...
>>>>
>>>> import std.stdio;
>>>>
>>>> void main() {
>>>> 	write("How many students are there? ");
>>>> 	int studentCount;
>>>> 	readf("%s", &studentCount);
>>>> 	write("How many teachers are there? ");
>>>> 	int teacherCount;
>>>> 	readf("%s", &teacherCount);
>>>>
>>>> 	writefln("Got it: there are %d students.", studentCount);
>>>> 	writefln("And there are %d teachers.", teacherCount);
>>>> }
>>>>
>>>>
>>>> When given the input...
>>>> 10 42
>>>>
>>>> will produce the error... std.conv.ConvException@/usr/include/dlang/dmd/std/conv.d(2013): Unexpected '4' when converting from type LockingTextReader to type int
>>>>
>>>> I understand what is wrong and how to fix it but the produced error is incorrect.
>>>
>>> To '\ n' does not remain in the input stream, it is necessary to write so:
>>> -----
>>> readf("%s ", &studentCount);
>>
>> I was meaning this as a bug report.
> 
> issues.dlang.org please, otherwise no-one will remember to fix it.

Submitted... or rather found a similar one and updated it. https://issues.dlang.org/show_bug.cgi?id=12260