week 121: 2 Perl scripts, 1 bash script

2 files changed, 53 insertions, 0 deletions

diff --git a/challenge-121/cheok-yin-fung/bash/ch-1.sh b/challenge-121/cheok-yin-fung/bash/ch-1.sh
new file mode 100644
index 0000000000..f2fec6ffc1
--- /dev/null
+++ b/challenge-121/cheok-yin-fung/bash/ch-1.sh
@@ -0,0 +1,40 @@
+#!/bin/bash                                                                     
+# The Weekly Challenge - 121                                                   
+# Task 1 Invert Bit                                                           
+# Usage: $ chmod +x ch-1.sh                                                     
+#        $ ./ch-1.sh n m                                                          
+
+n=$1
+m=$2
+
+if [ $n -gt 255 ] || [ $n -lt 0 ] ;
+then
+    echo "Integer within 0 to 255."
+    exit 
+fi
+
+t=$n
+c=0
+declare -a arr
+
+while [ $t -gt 0 ]
+do
+    c=$(($c+1))
+    if [ $c -ne $m ] ;
+        then arr+=($(($t%2)))
+        else arr+=($(($(($t%2+1))%2)))
+    fi
+    t=$(($t/2))
+done
+
+ans=0
+
+if [ $c -lt $m ];
+    then ans=$(($n+2**($m-1)))
+    else 
+        for (( i = 0 ; i < $c ; i++ )); do
+            ans=$(( $ans + $[arr[i]] * 2**i ))
+        done
+fi
+
+echo $ans
diff --git a/challenge-121/cheok-yin-fung/perl/ch-1.pl b/challenge-121/cheok-yin-fung/perl/ch-1.pl
new file mode 100644
index 0000000000..ef2293cbc2
--- /dev/null
+++ b/challenge-121/cheok-yin-fung/perl/ch-1.pl
@@ -0,0 +1,13 @@
+say ($ARGV[0] ^ (1 << $ARGV[1]-1));
+
+=pod
+ https://en.wikipedia.org/wiki/Bitwise_operation
+  #Truth_table_for_all_binary_logical_operators
+
+p q
+1 1 -> 0
+1 0 -> 1
+0 1 -> 1
+0 0 -> 0
+
+operation: XOR