digitalmars.D.learn - integer max, min?

Paolo Invernizzi (3/3) Oct 02 2007 Silly question...

BLS (4/9) Oct 02 2007 Have a look at :

downs (28/39) Oct 02 2007 Or if you mean the other max/min ...

Paolo Invernizzi (5/48) Oct 02 2007 God! It's an overkill!

Nathan Reed (18/23) Oct 02 2007 (a) If you're talking about the maximum and minimum values an int can

downs (8/12) Oct 02 2007 Actually, it only works with numbers. Most of the complicated-looking
Paolo Invernizzi (7/35) Oct 02 2007 Natan,

Bill Baxter (9/15) Oct 02 2007 Nope, crazy as it may seem it's not there. There's also no standard

Steven Schveighoffer (5/8) Oct 02 2007 try x < y ? x : y for min(x, y)

Paolo Invernizzi (6/20) Oct 02 2007 Thanks Steven,

Paolo Invernizzi <arathorn NO_SPAMfastwebnet.it> writes:

Silly question...

Where are in Phobos the max and min for integers?

Thanks, Paolo

Oct 02 2007

BLS <nanali nospam-wanadoo.fr> writes:

Paolo Invernizzi schrieb:
 Silly question...
 
 Where are in Phobos the max and min for integers?
 
 Thanks, Paolo

Have a look at :

http://www.digitalmars.com/d/property.html

HTH Bjoern

Oct 02 2007

downs <default_357-line yahoo.de> writes:

BLS wrote:
 Paolo Invernizzi schrieb:
 Silly question...

 Where are in Phobos the max and min for integers?

 Thanks, Paolo

 Have a look at :
 
 http://www.digitalmars.com/d/property.html
 
 HTH Bjoern

Or if you mean the other max/min ...

template supertype(T...) {
  static assert (T.length);
  static if (T.length==1)
    alias T[0] supertype;
  else static if (T.length==2)
    alias typeof(T[0].init+T[1].init) supertype;
  else
    alias supertype!(
      typeof(T[0].init+T[1].init),
      T[2..$]
    ) supertype;
}

supertype!(T) max(T...)(T t) {
  static assert(T.length);
  supertype!(T) res=t[0];
  foreach (v; t[1..$]) if (v>res) res=v;
  return res;
}

supertype!(T) min(T...)(T t) {
  static assert(T.length);
  supertype!(T) res=t[0];
  foreach (v; t[1..$]) if (v<res) res=v;
  return res;
}

That should work. Have fun!
 --downs

Oct 02 2007

Paolo Invernizzi <arathorn NO_SPAMfastwebnet.it> writes:

God! It's an overkill!

There's not in Phobos something like fmin fmax but for integers? Or must 
I always convert the result back from real?

Cheers, Paolo

downs wrote:
 BLS wrote:
 Paolo Invernizzi schrieb:
 Silly question...

 Where are in Phobos the max and min for integers?

 Thanks, Paolo

 Have a look at :

 http://www.digitalmars.com/d/property.html

 HTH Bjoern

 Or if you mean the other max/min ...
 
 template supertype(T...) {
   static assert (T.length);
   static if (T.length==1)
     alias T[0] supertype;
   else static if (T.length==2)
     alias typeof(T[0].init+T[1].init) supertype;
   else
     alias supertype!(
       typeof(T[0].init+T[1].init),
       T[2..$]
     ) supertype;
 }
 
 supertype!(T) max(T...)(T t) {
   static assert(T.length);
   supertype!(T) res=t[0];
   foreach (v; t[1..$]) if (v>res) res=v;
   return res;
 }
 
 supertype!(T) min(T...)(T t) {
   static assert(T.length);
   supertype!(T) res=t[0];
   foreach (v; t[1..$]) if (v<res) res=v;
   return res;
 }
 
 That should work. Have fun!
  --downs

Oct 02 2007

Nathan Reed <nathaniel.reed gmail.com> writes:

Paolo Invernizzi wrote:
 God! It's an overkill!
 
 There's not in Phobos something like fmin fmax but for integers? Or must 
 I always convert the result back from real?
 

(a) If you're talking about the maximum and minimum values an int can 
take on, they are named int.max and int.min.

(b) If you're talking about functions max(a,b) and min(a,b) that return 
the max and min of their arguments, see Downs' post, which is a bit 
overkill if you just want it on numeric types, but will (I think) do 
lexicographic comparison for string and array types.  If you just want 
to use it with numeric types (or types that have opCmp), this will do:

T min(T) (T a, T b)
{
     return (a < b) ? a : b;
}

T max(T) (T a, T b)
{
     return (a > b) ? a : b;
}

Thanks,
Nathan

Oct 02 2007

downs <default_357-line yahoo.de> writes:

Nathan Reed wrote:
 (b) If you're talking about functions max(a,b) and min(a,b) that return
 the max and min of their arguments, see Downs' post, which is a bit
 overkill if you just want it on numeric types, but will (I think) do
 lexicographic comparison for string and array types.

Actually, it only works with numbers. Most of the complicated-looking
code just determines the type that can hold all possible results (that's
what the supertype stuff is for). That's also the reason it won't work
with strings and arrays - they don't define "+". Sorry. ^^
But yeah, it is a bit overkill. Gets handy when you want to min/max more
than two values of different types.
 --downs

Oct 02 2007

Paolo Invernizzi <arathorn NO_SPAMfastwebnet.it> writes:

Natan,
I'm talking about the (b) case, sorry for the confusion.
I know I can use a template, I'm just wondering if THAT template was in 
some Phobos module, as I cannot find it!
I'm already including std.math, so I was only wondering why...

Cheers, Paolo

Nathan Reed wrote:
 Paolo Invernizzi wrote:
 God! It's an overkill!

 There's not in Phobos something like fmin fmax but for integers? Or 
 must I always convert the result back from real?

 
 (a) If you're talking about the maximum and minimum values an int can 
 take on, they are named int.max and int.min.
 
 (b) If you're talking about functions max(a,b) and min(a,b) that return 
 the max and min of their arguments, see Downs' post, which is a bit 
 overkill if you just want it on numeric types, but will (I think) do 
 lexicographic comparison for string and array types.  If you just want 
 to use it with numeric types (or types that have opCmp), this will do:
 
 T min(T) (T a, T b)
 {
     return (a < b) ? a : b;
 }
 
 T max(T) (T a, T b)
 {
     return (a > b) ? a : b;
 }
 
 Thanks,
 Nathan

Oct 02 2007

Bill Baxter <dnewsgroup billbaxter.com> writes:

Paolo Invernizzi wrote:
 Natan,
 I'm talking about the (b) case, sorry for the confusion.
 I know I can use a template, I'm just wondering if THAT template was in 
 some Phobos module, as I cannot find it!
 I'm already including std.math, so I was only wondering why...
 

Nope, crazy as it may seem it's not there.  There's also no standard 
swap() function like:

void swap(T)(ref T a, ref T b) {
     T tmp = a;
     a = b;
     b = tmp;
}

--bb

Oct 02 2007

"Steven Schveighoffer" <schveiguy yahoo.com> writes:

"Paolo Invernizzi" <arathorn NO_SPAMfastwebnet.it> wrote in message 
news:fdt65v$1306$1 digitalmars.com...
 Silly question...

 Where are in Phobos the max and min for integers?

 Thanks, Paolo

try x < y ? x : y for min(x, y)
and x > y ? x : y for max(x, y)

-Steve

Oct 02 2007

Paolo Invernizzi <arathorn NO_SPAMfastwebnet.it> writes:

Thanks Steven,
I know the ternary operator, and that's good for simple variable 
comparison, but if you use it in complex expressions, say also more than 
one times, sometimes it's not so readable as plain old min/max.

Paolo.

Steven Schveighoffer wrote:
 "Paolo Invernizzi" <arathorn NO_SPAMfastwebnet.it> wrote in message 
 news:fdt65v$1306$1 digitalmars.com...
 Silly question...

 Where are in Phobos the max and min for integers?

 Thanks, Paolo

 
 try x < y ? x : y for min(x, y)
 and x > y ? x : y for max(x, y)
 
 -Steve

Oct 02 2007

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digitalmars.D.learn - integer max, min?