Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 11:07:05 UTC, Rikki Cattermole wrote:
Sure when:
import std.traits : ReturnType;
import std.stdio : writeln;
static assert(is(ReturnType!writeln == int));
Thanks.
On Thursday, 9 April 2015 at 11:09:43 UTC, John Colvin wrote:
Yes, because writeln returns nothing, but why would you do
that? Just put the return on the next line, it's more readable.
Or, in the example above, just omit it entirely as the return
is implicit.
I quite often have to write similar designs:
-
import std.stdio;
void main() {
auto a = [ 1, 2, 3, 4, 5 ];
foreach (e; a) {
if (e == 4) {
writeln(Yes);
return;
}
}
writeln(No);
}
-
But is not it easier to write :)
import std.stdio;
void main() {
auto a = [ 1, 2, 3, 4, 5 ];
foreach (e; a) {
if (e == 4) {
return writeln(Yes);
}
}
writeln(No);
}
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 11:07:05 UTC, Rikki Cattermole wrote:
On 9/04/2015 11:03 p.m., Dennis Ritchie wrote:
Hi,
Is it allowed in D similar designs?
void main() {
import std.stdio;
return writeln(Hello, world!);
}
Sure when:
import std.traits : ReturnType;
import std.stdio : writeln;
static assert(is(ReturnType!writeln == int));
You might wanna check that :p
Re: return the other functions of the void main()
On 9/04/2015 11:22 p.m., John Colvin wrote:
On Thursday, 9 April 2015 at 11:07:05 UTC, Rikki Cattermole wrote:
On 9/04/2015 11:03 p.m., Dennis Ritchie wrote:
Hi,
Is it allowed in D similar designs?
void main() {
import std.stdio;
return writeln(Hello, world!);
}
Sure when:
import std.traits : ReturnType;
import std.stdio : writeln;
static assert(is(ReturnType!writeln == int));
You might wanna check that :p
No no, its valid D code. After all, as long as the compiler doesn't
assert, its perfectly valid. I was documenting the usage of return for
main function's when the return type of it is int.
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 17:38:42 UTC, Dennis Ritchie wrote: I think it has something to do with Vindovs :) *Windows
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 17:08:44 UTC, Dennis Ritchie wrote: Operates a code normally, but still gives the error: http://ideone.com/kDHMk5 I think it has something to do with Vindovs :) - http://dpaste.dzfl.pl/4c5bb9dd0ffa
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 11:09:43 UTC, John Colvin wrote:
On Thursday, 9 April 2015 at 11:04:00 UTC, Dennis Ritchie wrote:
Hi,
Is it allowed in D similar designs?
void main() {
import std.stdio;
return writeln(Hello, world!);
}
Yes, because writeln returns nothing, but why would you do
that? Just put the return on the next line, it's more readable.
Or, in the example above, just omit it entirely as the return
is implicit.
It's useful when writing generic wrappers, where you just want to
return whatever the wrapped function returns and don't want to
treat void functions differently.
I wouldn't use it in normal code, because it can be confusing, as
`return` usually indicates that a value is indeed returned.
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 11:04:00 UTC, Dennis Ritchie wrote:
Hi,
Is it allowed in D similar designs?
void main() {
import std.stdio;
return writeln(Hello, world!);
}
It seems that you can not do so because writeln() something back,
which leads to RUNTIME_ERROR in DMD 2.066.1:
OK:
-
import std.conv;
import std.stdio;
import std.string;
void main() {
int n = readln.strip.to!int;
string s = readln.strip;
foreach (from; 0 .. n)
foreach (jump; 1 .. n) {
bool ok;
foreach (i; 0 .. 5) {
int pos = from + i * jump;
if (pos = n || s[pos] != '*') {
ok = true;
break;
}
}
if (!ok)
return write(yes);
}
write(no);
}
-
http://codeforces.ru/contest/526/submission/10641745?locale=en
RUNTIME_ERROR:
-
import std.conv;
import std.stdio;
import std.string;
void main() {
int n = readln.strip.to!int;
string s = readln.strip;
foreach (from; 0 .. n)
foreach (jump; 1 .. n) {
bool ok;
foreach (i; 0 .. 5) {
int pos = from + i * jump;
if (pos = n || s[pos] != '*') {
ok = true;
break;
}
}
if (!ok)
return writeln(yes);
}
writeln(no);
}
-
http://codeforces.ru/contest/526/submission/10641695?locale=en
Re: return the other functions of the void main()
I quite often have to write similar designs:
-
import std.stdio;
void main() {
auto a = [ 1, 2, 3, 4, 5 ];
foreach (e; a) {
if (e == 4) {
writeln(Yes);
return;
}
}
writeln(No);
}
-
But is not it easier to write :)
import std.stdio;
void main() {
auto a = [ 1, 2, 3, 4, 5 ];
foreach (e; a) {
if (e == 4) {
return writeln(Yes);
}
}
writeln(No);
}
import std.stdio;
import std.algorithm;
import std.array;
void main() {
auto a = [ 1, 2, 3, 4, 5 ];
writeln(a.find(4).empty ? No : Yes);
}
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 16:02:01 UTC, Dennis Ritchie wrote:
On Thursday, 9 April 2015 at 11:04:00 UTC, Dennis Ritchie wrote:
Hi,
Is it allowed in D similar designs?
void main() {
import std.stdio;
return writeln(Hello, world!);
}
It seems that you can not do so because writeln() something
back, which leads to RUNTIME_ERROR in DMD 2.066.1:
OK:
-
import std.conv;
import std.stdio;
import std.string;
void main() {
int n = readln.strip.to!int;
string s = readln.strip;
foreach (from; 0 .. n)
foreach (jump; 1 .. n) {
bool ok;
foreach (i; 0 .. 5) {
int pos = from + i * jump;
if (pos = n || s[pos] != '*') {
ok = true;
break;
}
}
if (!ok)
return write(yes);
}
write(no);
}
-
http://codeforces.ru/contest/526/submission/10641745?locale=en
RUNTIME_ERROR:
-
import std.conv;
import std.stdio;
import std.string;
void main() {
int n = readln.strip.to!int;
string s = readln.strip;
foreach (from; 0 .. n)
foreach (jump; 1 .. n) {
bool ok;
foreach (i; 0 .. 5) {
int pos = from + i * jump;
if (pos = n || s[pos] != '*') {
ok = true;
break;
}
}
if (!ok)
return writeln(yes);
}
writeln(no);
}
-
http://codeforces.ru/contest/526/submission/10641695?locale=en
Try running your code somewhere where you can actually see the
output properly. RUNTIME_ERROR isn't something I recognise from D.
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 11:04:00 UTC, Dennis Ritchie wrote:
Hi,
Is it allowed in D similar designs?
void main() {
import std.stdio;
return writeln(Hello, world!);
}
Yes, because writeln returns nothing, but why would you do that?
Just put the return on the next line, it's more readable. Or, in
the example above, just omit it entirely as the return is
implicit.
Re: return the other functions of the void main()
On 9/04/2015 11:03 p.m., Dennis Ritchie wrote:
Hi,
Is it allowed in D similar designs?
void main() {
import std.stdio;
return writeln(Hello, world!);
}
Sure when:
import std.traits : ReturnType;
import std.stdio : writeln;
static assert(is(ReturnType!writeln == int));
Re: return the other functions of the void main()
Jack Applegame: writeln(a.find(4).empty ? No : Yes); canFind? Bye, bearophile
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 12:57:26 UTC, Jack Applegame wrote:
I quite often have to write similar designs:
-
import std.stdio;
void main() {
auto a = [ 1, 2, 3, 4, 5 ];
foreach (e; a) {
if (e == 4) {
writeln(Yes);
return;
}
}
writeln(No);
}
-
But is not it easier to write :)
import std.stdio;
void main() {
auto a = [ 1, 2, 3, 4, 5 ];
foreach (e; a) {
if (e == 4) {
return writeln(Yes);
}
}
writeln(No);
}
import std.stdio;
import std.algorithm;
import std.array;
void main() {
auto a = [ 1, 2, 3, 4, 5 ];
writeln(a.find(4).empty ? No : Yes);
}
import std.stdio;
void main() {
foreach (...) {
foreach (...) {
...
if (...) {
...
return writeln(Yes);
}
...
}
...
}
...
writeln(No);
}
No design can be completely arbitrary:
-
import std.stdio;
void main() {
foreach (...) {
foreach (...) {
...
if (...) {
...
return writeln(Yes);
}
...
}
...
}
...
writeln(No);
}
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 16:55:00 UTC, John Colvin wrote: Try running your code somewhere where you can actually see the output properly. RUNTIME_ERROR isn't something I recognise from D. Operates a code normally, but still gives the error: http://ideone.com/kDHMk5
Re: return the other functions of the void main()
On Thursday, 9 April 2015 at 11:38:26 UTC, Rikki Cattermole wrote:
On 9/04/2015 11:22 p.m., John Colvin wrote:
On Thursday, 9 April 2015 at 11:07:05 UTC, Rikki Cattermole
wrote:
On 9/04/2015 11:03 p.m., Dennis Ritchie wrote:
Hi,
Is it allowed in D similar designs?
void main() {
import std.stdio;
return writeln(Hello, world!);
}
Sure when:
import std.traits : ReturnType;
import std.stdio : writeln;
static assert(is(ReturnType!writeln == int));
You might wanna check that :p
I was documenting the usage of return for main function's when
the return type of it is int.
Ok... not sure how anyone was supposed to know that. The example
given used void main. Also, the return type of writeln is void,
so it's doubly confusing.
