Use methods to factor out calculations.

13 files changed, 106 insertions, 98 deletions

diff --git a/challenge-123/abigail/awk/ch-2.awk b/challenge-123/abigail/awk/ch-2.awk
index 27709d6fd0..96ac5314b1 100644
--- a/challenge-123/abigail/awk/ch-2.awk
+++ b/challenge-123/abigail/awk/ch-2.awk
@@ -8,13 +8,11 @@
 # Run as: awk -f ch-2.awk < input-file
 #
 
-{
-    e1 = ($1 - $3) ^ 2 + ($2 - $4) ^ 2
-    e2 = ($3 - $5) ^ 2 + ($4 - $6) ^ 2
-    e3 = ($5 - $7) ^ 2 + ($6 - $8) ^ 2
-    e4 = ($7 - $1) ^ 2 + ($8 - $2) ^ 2
-    d1 = ($1 - $5) ^ 2 + ($2 - $6) ^ 2
-    d2 = ($3 - $7) ^ 2 + ($4 - $8) ^ 2
+function dist (x1, y1, x2, y2) {(x1 - x2) ^ 2 + (y1 - y2) ^ 2}
 
-    print ((e1 == e2 && e2 == e3 && e3 == e4 && d1 == d2) ? 1 : 0)
+{
+    print (dist ($1, $2, $3, $4) == dist ($3, $4, $5, $6) &&
+           dist ($3, $4, $5, $6) == dist ($5, $6, $7, $8) &&
+           dist ($5, $6, $7, $8) == dist ($7, $8, $1, $2) &&
+           dist ($1, $2, $5, $6) == dist ($3, $4, $7, $8) ? 1 : 0)
 }
diff --git a/challenge-123/abigail/bash/ch-2.sh b/challenge-123/abigail/bash/ch-2.sh
index fb12779c2e..68844b2f46 100644
--- a/challenge-123/abigail/bash/ch-2.sh
+++ b/challenge-123/abigail/bash/ch-2.sh
@@ -10,13 +10,15 @@
 
 set -f
 
+function dist () {((dist = ($1 - $3) ** 2 + ($2 - $4) ** 2))}
+
 while read x1 y1 x2 y2 x3 y3 x4 y4
-do    ((e1 = (x1 - x2) ** 2 + (y1 - y2) ** 2))
-      ((e2 = (x2 - x3) ** 2 + (y2 - y3) ** 2))
-      ((e3 = (x3 - x4) ** 2 + (y3 - y4) ** 2))
-      ((e4 = (x4 - x1) ** 2 + (y4 - y1) ** 2))
-      ((d1 = (x1 - x3) ** 2 + (y1 - y3) ** 2))
-      ((d2 = (x2 - x4) ** 2 + (y2 - y4) ** 2))
+do    dist $x1 $y1 $x2 $y2; ((e1 = dist))
+      dist $x2 $y2 $x3 $y3; ((e2 = dist))
+      dist $x3 $y3 $x4 $y4; ((e3 = dist))
+      dist $x4 $y4 $x1 $y1; ((e4 = dist))
+      dist $x1 $y1 $x3 $y3; ((d1 = dist))
+      dist $x2 $y2 $x4 $y4; ((d2 = dist))
       if ((e1 == e2 && e2 == e3 && e3 == e4 && d1 == d2))
       then echo 1
       else echo 0
diff --git a/challenge-123/abigail/bc/ch-2.bc b/challenge-123/abigail/bc/ch-2.bc
index 2ea9169a08..70815c52d7 100644
--- a/challenge-123/abigail/bc/ch-2.bc
+++ b/challenge-123/abigail/bc/ch-2.bc
@@ -8,6 +8,8 @@
 # Input should be terminated with a line starting with a 0
 #
 
+define dist (a, b, c, d) {return ((a - c) ^ 2 + (b - d) ^ 2)}
+
 while (1) {
     a = read ()
     if (a == 0) {break}
@@ -18,15 +20,13 @@ while (1) {
     f = read ()
     g = read ()
     h = read ()
-    i = (a - c) ^ 2 + (b - d) ^ 2
-    j = (c - e) ^ 2 + (d - f) ^ 2
-    k = (e - g) ^ 2 + (f - h) ^ 2
-    l = (g - a) ^ 2 + (h - b) ^ 2
-    m = (a - e) ^ 2 + (b - f) ^ 2
-    n = (c - g) ^ 2 + (d - h) ^ 2
-    o = 0
-    if (i == j && j == k && k == l && m == n) {
-        o = 1
+
+    if (dist (a, b, c, d) == dist (c, d, e, f) && \
+        dist (c, d, e, f) == dist (e, f, g, h) && \
+        dist (e, f, g, h) == dist (g, h, a, b) && \
+        dist (a, b, e, f) == dist (c, d, g, h)) {
+        1
+    } else {
+        0
     }
-    o
 }
diff --git a/challenge-123/abigail/c/ch-2.c b/challenge-123/abigail/c/ch-2.c
index 56f0b615d4..60a24fb06b 100644
--- a/challenge-123/abigail/c/ch-2.c
+++ b/challenge-123/abigail/c/ch-2.c
@@ -10,19 +10,19 @@
  * Run as: cc -o ch-2.o ch-2.c; ./ch-2.o < input-file
  */
 
+int dist (int x1, int y1, int x2, int y2) {
+    return ((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
+}
+
 int main (void) {
     int x1, y1, x2, y2, x3, y3, x4, y4;
 
     while (scanf ("%d %d %d %d %d %d %d %d",
                    &x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4) == 8) {
-        int e1 = (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
-        int e2 = (x2 - x3) * (x2 - x4) + (y2 - y3) * (y2 - y3);
-        int e3 = (x3 - x4) * (x3 - x4) + (y3 - y4) * (y3 - y4);
-        int e4 = (x4 - x1) * (x4 - x1) + (y4 - y1) * (y4 - y1);
-        int d1 = (x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3);
-        int d2 = (x2 - x4) * (x2 - x4) + (y2 - y4) * (y2 - y4);
-
-        printf ("%d\n", e1 == e2 && e2 == e3 && e3 == e4 && d1 == d2 ? 1 : 0);
+        printf ("%d\n", dist (x1, y1, x2, y2) == dist (x2, y2, x3, y3) &&
+                        dist (x2, y2, x3, y3) == dist (x3, y3, x4, y4) &&
+                        dist (x3, y3, x4, y4) == dist (x4, y4, x1, y1) &&
+                        dist (x1, y1, x3, y3) == dist (x2, y2, x4, y4) ? 1 : 0);
     }
 
     return (0);
diff --git a/challenge-123/abigail/go/ch-2.go b/challenge-123/abigail/go/ch-2.go
index 37d275d5dc..6a287f6d73 100644
--- a/challenge-123/abigail/go/ch-2.go
+++ b/challenge-123/abigail/go/ch-2.go
@@ -12,22 +12,23 @@ import (
     "fmt"
 )
 
+func dist (x1 int, y1 int, x2 int, y2 int) int {
+    return (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
+}
+
 func main () {
-    var x1, y1, x2, y2, x3, y3, x4, y4, e1, e2, e3, e4, d1, d2 int;
+    var x1, y1, x2, y2, x3, y3, x4, y4 int;
     for {
         var n, err = fmt . Scanf ("%d %d %d %d %d %d %d %d",
                                    &x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4);
         if (err != nil || n != 8) {
             break;
         }
-        e1 = (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
-        e2 = (x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3);
-        e3 = (x3 - x4) * (x3 - x4) + (y3 - y4) * (y3 - y4);
-        e4 = (x4 - x1) * (x4 - x1) + (y4 - y1) * (y4 - y1);
-        d1 = (x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3);
-        d2 = (x2 - x4) * (x2 - x4) + (y2 - y4) * (y2 - y4);
 
-        if (e1 == e2 && e2 == e3 && e3 == e4 && d1 == d2) {
+        if (dist (x1, y1, x2, y2) == dist (x2, y2, x3, y3) &&
+            dist (x2, y2, x3, y3) == dist (x3, y3, x4, y4) &&
+            dist (x3, y3, x4, y4) == dist (x4, y4, x1, y1) &&
+            dist (x1, y1, x3, y3) == dist (x2, y2, x4, y4)) {
             fmt . Printf ("%d\n", 1);
         } else { // Seriously, go, else needs to be cuddled?
             fmt . Printf ("%d\n", 0);
diff --git a/challenge-123/abigail/java/ch-2.java b/challenge-123/abigail/java/ch-2.java
index 8d13bcf8bf..24f7dbe9a9 100644
--- a/challenge-123/abigail/java/ch-2.java
+++ b/challenge-123/abigail/java/ch-2.java
@@ -9,6 +9,9 @@
 import java.util.*;
 
 public class ch2 {
+    static int dist (int x1, int y1, int x2, int y2) {
+        return (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
+    }
     public static void main (String [] args) {
         Scanner scanner = new Scanner (System . in);
         while (scanner . hasNext ()) {
@@ -21,15 +24,11 @@ public class ch2 {
             int x4 = scanner . nextInt ();
             int y4 = scanner . nextInt ();
 
-            int e1 = (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
-            int e2 = (x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3);
-            int e3 = (x3 - x4) * (x3 - x4) + (y3 - y4) * (y3 - y4);
-            int e4 = (x4 - x1) * (x4 - x1) + (y4 - y1) * (y4 - y1);
-            int d1 = (x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3);
-            int d2 = (x2 - x4) * (x2 - x4) + (y2 - y4) * (y2 - y4);
-
-            System . out . println (e1 == e2 && e2 == e3 &&
-                                    e3 == e4 && d1 == d2 ? 1 : 0);
+            System . out . println (
+                dist (x1, y1, x2, y2) == dist (x2, y2, x3, y3) &&
+                dist (x2, y2, x3, y3) == dist (x3, y3, x4, y4) &&
+                dist (x3, y3, x4, y4) == dist (x4, y4, x1, y1) &&
+                dist (x1, y1, x3, y3) == dist (x2, y2, x4, y4) ? 1 : 0);
         }
     }
 }
diff --git a/challenge-123/abigail/lua/ch-2.lua b/challenge-123/abigail/lua/ch-2.lua
index b379f3078a..ddf8d86a14 100644
--- a/challenge-123/abigail/lua/ch-2.lua
+++ b/challenge-123/abigail/lua/ch-2.lua
@@ -13,16 +13,16 @@ for _ = 2, 8 do
     pat = pat .. "%s+(-?%d+)";
 end
 
+function dist (x1, y1, x2, y2)
+    return (x1 - x2) ^ 2 + (y1 - y2) ^ 2
+end
 
 for line in io . lines () do
     _, _, x1, y1, x2, y2, x3, y3, x4, y4 = line : find (pat)
-    local e1 = (x1 - x2) ^ 2 + (y1 - y2) ^ 2
-    local e2 = (x2 - x3) ^ 2 + (y2 - y3) ^ 2
-    local e3 = (x3 - x4) ^ 2 + (y3 - y4) ^ 2
-    local e4 = (x4 - x1) ^ 2 + (y4 - y1) ^ 2
-    local d1 = (x1 - x3) ^ 2 + (y1 - y3) ^ 2
-    local d2 = (x2 - x4) ^ 2 + (y2 - y4) ^ 2
-    if  e1 == e2 and e2 == e3 and e3 == e4 and d1 == d2 then
+    if  dist (x1, y1, x2, y2) == dist (x2, y2, x3, y3) and
+        dist (x2, y2, x3, y3) == dist (x3, y3, x4, y4) and
+        dist (x3, y3, x4, y4) == dist (x4, y4, x1, y1) and
+        dist (x1, y1, x3, y3) == dist (x2, y2, x4, y4) then
         print (1)
     else
         print (0)
diff --git a/challenge-123/abigail/node/ch-2.js b/challenge-123/abigail/node/ch-2.js
index 85ec5ce186..8e5fdb499e 100644
--- a/challenge-123/abigail/node/ch-2.js
+++ b/challenge-123/abigail/node/ch-2.js
@@ -8,15 +8,16 @@
 // Run as: node ch-2.js < input-file
 //
 
+function dist (x1, y1, x2, y2) {
+    return (x1 - x2) ** 2 + (y1 - y2) ** 2
+}
+
   require ('readline')
 . createInterface ({input: process . stdin})   
 . on              ('line', line => {
     let [x1, y1, x2, y2, x3, y3, x4, y4] = line . split (/ +/) . map (_ => +_)
-    let e1 = (x1 - x2) ** 2 + (y1 - y2) ** 2
-    let e2 = (x2 - x3) ** 2 + (y2 - y3) ** 2
-    let e3 = (x3 - x4) ** 2 + (y3 - y4) ** 2
-    let e4 = (x4 - x1) ** 2 + (y4 - y1) ** 2
-    let d1 = (x1 - x3) ** 2 + (y1 - y3) ** 2
-    let d2 = (x2 - x4) ** 2 + (y2 - y4) ** 2
-    console . log (e1 == e2 && e2 == e3 && e3 == e4 && d1 == d2 ? 1 : 0)
+    console . log (dist (x1, y1, x2, y2) == dist (x2, y2, x3, y3) &&
+                   dist (x2, y2, x3, y3) == dist (x3, y3, x4, y4) &&
+                   dist (x3, y3, x4, y4) == dist (x4, y4, x1, y1) &&
+                   dist (x1, y1, x3, y3) == dist (x2, y2, x4, y4) ? 1 : 0)
 })
diff --git a/challenge-123/abigail/pascal/ch-2.p b/challenge-123/abigail/pascal/ch-2.p
index d71fa1c2f0..3bd63c819a 100644
--- a/challenge-123/abigail/pascal/ch-2.p
+++ b/challenge-123/abigail/pascal/ch-2.p
@@ -8,20 +8,21 @@ Program IsSquare;
 (* Run as: fpc -och-2.out ch-2.p; ./ch-2.out < input-file *)
 (*                                                        *)
 
+function dist (x1, y1, x2, y2: integer): integer;
+begin
+    dist := (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)
+end;
+
 var
     x1, y1, x2, y2, x3, y3, x4, y4: integer;
-    e1, e2, e3, e4, d1, d2: integer;
 
 begin
     while not eof () do begin
         readln (x1, y1, x2, y2, x3, y3, x4, y4);
-        e1 := (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
-        e2 := (x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3);
-        e3 := (x3 - x4) * (x3 - x4) + (y3 - y4) * (y3 - y4);
-        e4 := (x4 - x1) * (x4 - x1) + (y4 - y1) * (y4 - y1);
-        d1 := (x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3);
-        d2 := (x2 - x4) * (x2 - x4) + (y2 - y4) * (y2 - y4);
-        if (e1 = e2) and (e2 = e3) and (e3 = e4) and (d1 = d2) then begin
+        if (dist (x1, y1, x2, y2) = dist (x2, y2, x3, y3)) and
+           (dist (x2, y2, x3, y3) = dist (x3, y3, x4, y4)) and
+           (dist (x3, y3, x4, y4) = dist (x4, y4, x1, y1)) and
+           (dist (x1, y1, x3, y3) = dist (x2, y2, x4, y4)) then begin
             writeln (1);
         end
         else begin
diff --git a/challenge-123/abigail/perl/ch-2.pl b/challenge-123/abigail/perl/ch-2.pl
index 7803ed57b0..6662c53e32 100644
--- a/challenge-123/abigail/perl/ch-2.pl
+++ b/challenge-123/abigail/perl/ch-2.pl
@@ -22,12 +22,15 @@ use experimental 'lexical_subs';
 # So we check whether all edges are equal, and whether both diagonals are equal.
 #
 
+#
+# Given the coordinates of two points, return the square of
+# the distance between them.
+#
+sub dist ($x1, $y1, $x2, $y2) {($x1 - $x2) ** 2 + ($y1 - $y2) ** 2}
+
 while (<>) {
-    my ($x1, $y1, $x2, $y2, $x3, $y3, $x4, $y4) = split;
-    say + ($x1 - $x2) ** 2 + ($y1 - $y2) ** 2 ==
-          ($x2 - $x3) ** 2 + ($y2 - $y3) ** 2 ==
-          ($x3 - $x4) ** 2 + ($y3 - $y4) ** 2 ==
-          ($x4 - $x1) ** 2 + ($y4 - $y1) ** 2 &&
-          ($x1 - $x3) ** 2 + ($y1 - $y3) ** 2 ==
-          ($x2 - $x4) ** 2 + ($y2 - $y4) ** 2 ? 1 : 0
+    my  ($x1, $y1, $x2, $y2, $x3, $y3, $x4, $y4) = split;
+    say dist ($x1, $y1, $x2, $y2) == dist ($x2, $y2, $x3, $y3) ==
+        dist ($x3, $y3, $x4, $y4) == dist ($x4, $y4, $x1, $x2) &&
+        dist ($x1, $y1, $x3, $y3) == dist ($x2, $y2, $x4, $y4) ? 1 : 0
 }
diff --git a/challenge-123/abigail/python/ch-2.py b/challenge-123/abigail/python/ch-2.py
index e61a2cc0c5..437dc072ff 100644
--- a/challenge-123/abigail/python/ch-2.py
+++ b/challenge-123/abigail/python/ch-2.py
@@ -10,15 +10,15 @@
 
 import fileinput
 
+def dist (x1, y1, x2, y2):
+    return (x1 - x2) ** 2 + (y1 - y2) ** 2
+
 for line in fileinput . input ():
     [x1, y1, x2, y2, x3, y3, x4, y4] = \
          map (lambda x: int (x), line . split (' '))
-    if (x1 - x2) ** 2 + (y1 - y2) ** 2 ==   \
-       (x2 - x3) ** 2 + (y2 - y3) ** 2 ==   \
-       (x3 - x4) ** 2 + (y3 - y4) ** 2 ==   \
-       (x4 - x1) ** 2 + (y4 - y1) ** 2 and  \
-       (x1 - x3) ** 2 + (y1 - y3) ** 2 ==   \
-       (x2 - x4) ** 2 + (y2 - y4) ** 2:
+    if dist (x1, y1, x2, y2) == dist (x2, y2, x3, y3) ==  \
+       dist (x3, y3, x4, y4) == dist (x4, y4, x1, y1) and \
+       dist (x1, y1, x3, y3) == dist (x2, y2, x4, y4):
         print (1)
     else:
         print (0)
diff --git a/challenge-123/abigail/ruby/ch-2.rb b/challenge-123/abigail/ruby/ch-2.rb
index 7e7f54b680..56fb532063 100644
--- a/challenge-123/abigail/ruby/ch-2.rb
+++ b/challenge-123/abigail/ruby/ch-2.rb
@@ -8,14 +8,16 @@
 # Run as: ruby ch-2.rb < input-file
 #
 
+def dist (x1, y1, x2, y2)
+    return (x1 - x2) ** 2 + (y1 - y2) ** 2
+end
+
 ARGF . each_line do
     |line|
     x1, y1, x2, y2, x3, y3, x4, y4 = line . split(" ") . map {|n| n . to_i}
-    e1 = (x1 - x2) ** 2 + (y1 - y2) ** 2
-    e2 = (x2 - x3) ** 2 + (y2 - y3) ** 2
-    e3 = (x3 - x4) ** 2 + (y3 - y4) ** 2
-    e4 = (x4 - x1) ** 2 + (y4 - y1) ** 2
-    d1 = (x1 - x3) ** 2 + (y1 - y3) ** 2
-    d2 = (x2 - x4) ** 2 + (y2 - y4) ** 2
-    puts (e1 == e2 && e2 == e3 && e3 == e4 && d1 == d2 ? 1 : 0)
+
+    puts (dist(x1, y1, x2, y2) == dist(x2, y2, x3, y3) &&
+          dist(x2, y2, x3, y3) == dist(x3, y3, x4, y4) &&
+          dist(x3, y3, x4, y4) == dist(x4, y4, x1, y1) &&
+          dist(x1, y1, x3, y3) == dist(x2, y2, x4, y4) ? 1 : 0)
 end
diff --git a/challenge-123/abigail/tcl/ch-2.tcl b/challenge-123/abigail/tcl/ch-2.tcl
index ee5ed1563e..2f0ad1e8a3 100644
--- a/challenge-123/abigail/tcl/ch-2.tcl
+++ b/challenge-123/abigail/tcl/ch-2.tcl
@@ -6,15 +6,16 @@
 # Run as: tclsh ch-2.tcl < input-file
 #
 
+proc dist {x1 y1 x2 y2} {
+    return [expr ($x1 - $x2) * ($x1 - $x2) + ($y1 - $y2) * ($y1 - $y2)]
+}
+
 while {[gets stdin line] >= 0} {
     lassign [split $line " "] x1 y1 x2 y2 x3 y3 x4 y4
-    set e1 [expr ($x1 - $x2) * ($x1 - $x2) + ($y1 - $y2) * ($y1 - $y2)]
-    set e2 [expr ($x2 - $x3) * ($x2 - $x3) + ($y2 - $y3) * ($y2 - $y3)]
-    set e3 [expr ($x3 - $x4) * ($x3 - $x4) + ($y3 - $y4) * ($y3 - $y4)]
-    set e4 [expr ($x4 - $x1) * ($x4 - $x1) + ($y4 - $y1) * ($y4 - $y1)]
-    set d1 [expr ($x1 - $x3) * ($x1 - $x3) + ($y1 - $y3) * ($y1 - $y3)]
-    set d2 [expr ($x2 - $x4) * ($x2 - $x4) + ($y2 - $y4) * ($y2 - $y4)]
-    if {$e1 == $e2 && $e2 == $e3 && $e3 == $e4 && $d1 == $d2} {
+    if {[dist $x1 $y1 $x2 $y2] == [dist $x2 $y2 $x3 $y3] &&
+        [dist $x2 $y2 $x3 $y3] == [dist $x3 $y3 $x4 $y4] &&
+        [dist $x3 $y3 $x4 $y4] == [dist $x4 $y4 $x1 $y1] &&
+        [dist $x1 $y1 $x3 $y3] == [dist $x2 $y2 $x4 $y4]} {
         puts 1
     } else {
         puts 0