June 2018 Update

Task/Loops-While/00DESCRIPTION

@@ -6,4 +6,20 @@ Start an integer value at   '''1024'''.
 Loop while it is greater than zero.
 
 Print the value (with a newline) and divide it by two each time through the loop.
+
+
+;Related tasks:
+*   [[Loop over multiple arrays simultaneously]]
+*   [[Loops/Break]]
+*   [[Loops/Continue]]
+*   [[Loops/Do-while]]
+*   [[Loops/Downward for]]
+*   [[Loops/For]]
+*   [[Loops/For with a specified step]]
+*   [[Loops/Foreach]]
+*   [[Loops/Increment loop index within loop body]]
+*   [[Loops/Infinite]]
+*   [[Loops/N plus one half]]
+*   [[Loops/Nested]]
+*   [[Loops/While]]
 <br><br>

Task/Loops-While/BASIC/loops-while-3.basic

@@ -0,0 +1,6 @@
+10 N% = 1024
+20 IF N% = 0 THEN 60
+30 PRINT N%
+40 N% = N%/2
+50 GOTO 20
+60 END

Task/Loops-While/C++/loops-while-1.cpp

@@ -1,5 +1,5 @@
 int i = 1024;
-while(i > 0) {
+while(i > 0){
   std::cout << i << std::endl;
   i /= 2;
 }

Task/Loops-While/C++/loops-while-2.cpp

@@ -1,2 +1,2 @@
-for (int i = 1024; i>0; i /= 2)
+for(int i = 1024; i > 0; i /= 2)
   std::cout << i << std::endl;

Task/Loops-While/C++/loops-while-3.cpp

@@ -1,2 +1,3 @@
-for (init; cond; update)
+for(init; cond; update){
   statement;
+}

Task/Loops-While/C++/loops-while-4.cpp

@@ -1,7 +1,6 @@
 {
   init;
-  while (cond)
-  {
+  while(cond){
     statement;
     update;
   }

Task/Loops-While/Fortress/loops-while.fortress

@@ -0,0 +1,9 @@
+component loops_while
+  export Executable
+
+  var i:ZZ32 = 1024
+  run() = while i > 0 do
+    println(i)
+    i := i DIV 2
+  end
+end

Task/Loops-While/Haskell/loops-while-1.hs

@@ -1,4 +1,5 @@
 import Control.Monad (when)
+
 main = loop 1024
   where loop n = when (n > 0)
                       (do print n

Task/Loops-While/Haskell/loops-while-2.hs

@@ -1,5 +1,10 @@
-import Control.Monad (when)
+import Data.IORef
+import Control.Monad.Loops
 
-whileM :: (Monad m) => m Bool -> m a -> m ()
-whileM cond body = do c <- cond
-                      when c (body >> whileM cond body)
+main :: IO ()
+main = do r <- newIORef 1024
+          whileM_ (do n <- readIORef r
+                     return (n > 0))
+                  (do n <- readIORef r
+                     print n
+                     modifyIORef r (`div` 2))

Task/Loops-While/Haskell/loops-while-3.hs

@@ -1,9 +1,11 @@
+{-# LANGUAGE MonadComprehensions #-}
 import Data.IORef
+import Control.Monad.Loops
 
 main :: IO ()
-main = do r <- newIORef 1024
-          whileM (do n <- readIORef r
-                     return (n > 0))
-                 (do n <- readIORef r
-                     print n
-                     modifyIORef r (`div` 2))
+main = do
+   r <- newIORef 1024
+   whileM_ [n > 0 | n <- readIORef r] $ do
+        n <- readIORef r
+        print n
+        modifyIORef r (`div` 2)

Task/Loops-While/PL-SQL/loops-while.sql

@@ -0,0 +1,10 @@
+set serveroutput on
+declare
+  n number := 1024;
+begin
+  while n > 0 loop
+    dbms_output.put_line(n);
+    n := trunc(n / 2);
+  end loop;
+end;
+/

Task/Loops-While/Perl/loops-while-1.pl

@@ -1,5 +1,5 @@
 my $n = 1024;
-while ($n) {
+while($n){
     print "$n\n";
     $n = int $n / 2;
 }

Task/Loops-While/Perl/loops-while-2.pl

@@ -1,5 +1,3 @@
-my $n = 1024;
-until ($n <= 0) {
+for(my $n = 1024; $n > 0; $n >>= 1){
     print "$n\n";
-    $n = int $n / 2;
 }

Task/Loops-While/Perl/loops-while-3.pl

@@ -0,0 +1,5 @@
+my $n = 1024;
+until($n == 0){
+    print "$n\n";
+    $n = int $n / 2;
+}

Task/Loops-While/X86-Assembly/loops-while.x86

@@ -0,0 +1,40 @@
+; NASM 64 bit X86-64 assembly on Linux
+
+global main
+extern printf
+
+segment .data
+
+printffmt db `%ld\n`,0
+
+segment .text
+
+main:	
+    push rbp
+    mov rbp,rsp
+
+; used rbx and r12 because printf preserves these values
+
+    mov rbx,1024                 ; start with 1024
+    mov r12,2                    ; load 2 as divisor
+
+.toploop                         ; top of while loop
+    cmp rbx,0                    ; compare to 0
+    jle .done                    ; exit 0 or less
+
+    lea rdi,[printffmt]          ; print number in rsi
+    mov rsi,rbx                  ; mov to rsi as argument
+    call printf
+
+; calculate n/2 and save
+    xor rdx,rdx                  ; clear rdx for division
+    mov rax,rbx                  ; mov number to rax for division
+    idiv r12                     ; divide by 2
+    mov rbx,rax                  ; save n/2
+
+    jmp .toploop                 ; next loop
+
+.done
+    xor rax,rax                  ; return code 0
+    leave                        ; fix stack
+    ret                          ; return