Hi,
Tell me, please, why this code works correctly always:

import std.stdio;

int n;
readf("%s\n", &n);

string s, t;
readf("%s\n%s\n", &s, &t);

And this code works correctly is not always:

import std.stdio;

readf("%s\n", &n);

char[200010] s, t;
scanf("%s%s", s.ptr, t.ptr);

Data is entered only in this format (n - the length of strings str1 and str2, 1 <= n <= 200000; only lowercase letters):

n
str1
str2

For example:

5
cater
doger

On Saturday, 21 March 2015 at 08:37:59 UTC, Dennis Ritchie wrote:
> Tell me, please, why this code works correctly always:
[...]
> And this code works correctly is not always:
>
> import std.stdio;
>
> readf("%s\n", &n);
>
> char[200010] s, t;
> scanf("%s%s", s.ptr, t.ptr);

Please go into more detail about how it doesn't work.

On Saturday, 21 March 2015 at 12:08:05 UTC, anonymous wrote:
> Please go into more detail about how it doesn't work.

Task:
http://codeforces.com/contest/527/problem/B?locale=en

It works:

char[200010] s, t;
s = readln.strip;
t = readln.strip;

http://codeforces.com/contest/527/submission/10377392?locale=en

 	
It doesn't always work:

char[200010] s, t;
scanf("%s%s", s.ptr, t.ptr);

http://codeforces.com/contest/527/submission/10376852?locale=en

P.S. I can't copy test №23 completely.

In C++ it is fully working:

char s[200005], t[200005];
scanf("%s%s", s, t);

http://codeforces.com/contest/527/submission/10376381?locale=en

On Saturday, 21 March 2015 at 14:31:20 UTC, Dennis Ritchie wrote:
> In C++ it is fully working:
>
> char s[200005], t[200005];
> scanf("%s%s", s, t);

Indeed.

Generate a 100000-character string:
-----
import std.range, std.stdio;
void main () {'a'.repeat (100000).writeln;}
-----

Try to copy it with D scanf and printf:
-----
import std.stdio;
void main () {
	char [100000] a;
	scanf ("%s", a.ptr);
	printf ("%s\n", a.ptr);
}
-----

Only 32767 first characters of the string are actually copied.

On Saturday, 21 March 2015 at 15:05:56 UTC, Ivan Kazmenko wrote:
> On Saturday, 21 March 2015 at 14:31:20 UTC, Dennis Ritchie wrote:
>> In C++ it is fully working:
>>
>> char s[200005], t[200005];
>> scanf("%s%s", s, t);
>
> Indeed.

And why in D copied only the first 32767 characters of the string? I'm more days couldn't understand what was going on...

> Generate a 100000-character string:
> -----
> import std.range, std.stdio;
> void main () {'a'.repeat (100000).writeln;}
> -----
>
> Try to copy it with D scanf and printf:
> -----
> import std.stdio;
> void main () {
> 	char [100000] a;
> 	scanf ("%s", a.ptr);
> 	printf ("%s\n", a.ptr);
> }
> -----
>
> Only 32767 first characters of the string are actually copied.

Thank you very much.

On 2015-03-21 at 16:05, Ivan Kazmenko wrote:
> Generate a 100000-character string
>[...]
> Try to copy it with D scanf and printf:
> -----
> import std.stdio;
> void main () {
>      char [100000] a;
>      scanf ("%s", a.ptr);
>      printf ("%s\n", a.ptr);
> }
> -----
>
> Only 32767 first characters of the string are actually copied.

In what universe?! Which OS, compiler and architecture?

On Saturday, 21 March 2015 at 19:09:59 UTC, FG wrote:
> In what universe?! Which OS, compiler and architecture?

On Saturday, 21 March 2015 at 19:09:59 UTC, FG wrote:
> In what universe?! Which OS, compiler and architecture?

Windows 8.1 x64, dmd 2.066.1:

import std.range, std.stdio;

void main () {

     stdout = File("in.txt", "w");

     'a'.repeat(100000).writeln;
}

import std.stdio;
import std.cstream;

void main () {

     freopen("in.txt", "r", din.file);
     freopen("out.txt", "w", dout.file);

     char[100000] a;

     scanf("%s", a.ptr);

     int lenA;
     foreach (i; 0 .. 100000) {
         if (a[i] == 'a')
             ++lenA;
         printf("%c", a[i]);
     }

     printf("\n%d\n", lenA); // 32767
}

By the way, in Ubuntu 14.04 LTS (dmd 2.066.1) everything works
fine:
#!/usr/bin/rdmd

import std.range, std.stdio;

void main () {

     stdout = File("in.txt", "w");

     'a'.repeat(100000).writeln;
}

#!/usr/bin/rdmd

import std.stdio;
import std.cstream;

void main () {

     freopen("in.txt", "r", din.file);
     freopen("out.txt", "w", dout.file);

     char[100000] a;

     scanf("%s", a.ptr);

     int lenA;
     foreach (i; 0 .. 100000) {
         if (a[i] == 'a')
             ++lenA;
         printf("%c", a[i]);
     }

     printf("\n%d\n", lenA); // 100000
}

On Saturday, 21 March 2015 at 15:05:56 UTC, Ivan Kazmenko wrote:
> Generate a 100000-character string:
> -----
> import std.range, std.stdio;
> void main () {'a'.repeat (100000).writeln;}
> -----
>
> Try to copy it with D scanf and printf:
> -----
> import std.stdio;
> void main () {
> 	char [100000] a;
> 	scanf ("%s", a.ptr);
> 	printf ("%s\n", a.ptr);
> }
> -----
>
> Only 32767 first characters of the string are actually copied.

That doesn't happen on linux, but I could reproduce it in wine. Seems to be a bug in the C runtime (snn.lib). I filed an issue:
https://issues.dlang.org/show_bug.cgi?id=14315

On 2015-03-21 at 21:02, Dennis Ritchie wrote:
>> In what universe?! Which OS, compiler and architecture?
> Windows 8.1 x64, dmd 2.066.1:

That's strange. I cannot recreate the problem on Win7 x64 with dmd 2.066.1, neither when compiled for 32- nor 64-bit. I have saved the a's to a file and use input redirect to load it, while the program is as follows:

import std.stdio;
void main () {
    char [100000] a;
    scanf ("%s", a.ptr);
    printf ("%s\n", a.ptr);
}


>       freopen("in.txt", "r", din.file);

No, that approach didn't change the result. I still get 10000.