3 files changed, 101 insertions, 6 deletions
diff --git a/challenge-120/cheok-yin-fung/bash/ch-1.sh b/challenge-120/cheok-yin-fung/bash/ch-1.sh
new file mode 100644
index 0000000000..d29d92261f
--- /dev/null
+++ b/challenge-120/cheok-yin-fung/bash/ch-1.sh
@@ -0,0 +1,36 @@
+#!/bin/bash
+# The Weekly Challenge - 120
+# Task 1 Swap Odd/Even Bits
+# Usage: $ chmod +x ch-1.sh
+#        $ ./ch-1.sh N
+
+N=$1
+
+if [ $N -gt 255 ] || [ $N -lt 1 ] ;
+then 
+    echo "Integer within 1 to 255."
+    exit ;
+fi
+
+x=$N
+
+qp () {
+    A=$(($1/2));
+    B=$(($1%2));
+    echo $(($B*2+$A))
+}
+
+while [ $x -ne 0 ]
+do
+    arr+=($(qp $x%4))
+    x=$(($x/4))
+done
+
+ANS=0
+
+for ((i=$((${#arr[@]}-1)); i>=0; i=$i-1))
+do
+    ANS=$(($ANS*4+$[arr[$i]]))
+done
+
+echo $ANS
diff --git a/challenge-120/cheok-yin-fung/bash/ch-2.sh b/challenge-120/cheok-yin-fung/bash/ch-2.sh
new file mode 100644
index 0000000000..26207114da
--- /dev/null
+++ b/challenge-120/cheok-yin-fung/bash/ch-2.sh
@@ -0,0 +1,47 @@
+#!/bin/bash
+# The Weekly Challenge - 120 
+# Task 2 Clock Angle
+# Usage: $ chmod +x ch-2.sh
+#        $ ./ch-2.sh hh mm
+
+# current time: date +"%H:%M"
+
+hr_hand_inc_per_deg=2    #unit: minute per degree
+
+minute_hand_rate=6         #unit: degree per minute
+
+h=$1
+m=$2
+
+deg_h=$((($h*30+$m/$hr_hand_inc_per_deg)%360))
+deg_m=$((($minute_hand_rate*$m)%360 ))
+half=0
+if [ $(($m%$hr_hand_inc_per_deg)) -eq 1 ];
+then
+    half=5
+    if [ $deg_h -gt $deg_m ];
+    then
+        deg_h=$(($deg_h))
+    else
+        deg_h=$(($deg_h+1))
+    fi
+fi
+
+if [ $deg_h -ge $deg_m ];
+then
+    deg=$(($deg_h-$deg_m))
+else
+    deg=$(($deg_m-$deg_h))
+fi
+
+if [ $deg -gt 180 ];
+then
+    if [ $half -eq 5 ];
+    then
+        deg=$((361-$deg))
+    else
+        deg=$((360-$deg))
+    fi
+fi
+
+echo $deg.$half deg
diff --git a/challenge-120/cheok-yin-fung/perl/ch-2.pl b/challenge-120/cheok-yin-fung/perl/ch-2.pl
index 7b607cc8c2..b626643592 100644
--- a/challenge-120/cheok-yin-fung/perl/ch-2.pl
+++ b/challenge-120/cheok-yin-fung/perl/ch-2.pl
@@ -4,25 +4,33 @@
 # Usage: $ ch-2.pl "hh:mm"
 use strict;
 use warnings;
-use Test::More tests => 5;
+use Test::More tests => 9;
 
-my $T = $ARGV[0] || 0;
+my @now = localtime(time);
 
-unless ($T =~ m/^(\d\d):(\d\d)$/ && $1 <= 24 && $2 <= 59) { 
+my $T = $ARGV[0] || "$now[2]:$now[1]";
+
+unless ($T =~ m/^(\d){1,2}:(\d){1,2}$/ && $1 <= 24 && $2 <= 59) { 
     die "Please input time in the format \"hh:mm\". \n";
 }
 
 #unit: degree(s) per minute
 my $hour_hand_rate = 0.5;
-my $minute_hand_rate = 6;
+my $minute_hand_rate = 6.0;
 
-print clock_angle($T), " degree", "\n";
+print "The clock angle of NOW ($T): " if !defined($ARGV[0]);
+print clock_angle($T), " deg";
+print " ± 5.5 deg" if !defined($ARGV[0]);
+print "\n";
 
 sub clock_angle {
     my $time = $_[0];
     my $h = substr($time,0,2);
     my $m = substr($time,-2,2);
-    my $deg = abs( ($h*30+$hour_hand_rate*$m - $minute_hand_rate*$m)) % 360;
+    my $deg = abs(($h*30+$hour_hand_rate*$m - $minute_hand_rate*$m));
+    while ($deg >= 360) {
+        $deg-=360;
+    }
     return $deg > 180 ? 360-$deg : $deg;
 }
 
@@ -32,3 +40,7 @@ ok ( clock_angle("04:00") == 120 , "Example 2");
 ok ( clock_angle("12:00") == 0 , "noon");
 ok ( clock_angle("06:00") == 180, "6 o'clock");
 ok ( clock_angle("09:00") == 90, "9 o'clock");
+ok ( clock_angle("11:59") == 5.5, "11:59");
+ok ( clock_angle("12:01") == 5.5, "12:01");
+ok ( clock_angle("09:27") == 121.5, "09:27");
+ok ( clock_angle("16:11") == 59.5, "16:11");