diff --git a/Backtracking/NQueen.js b/Backtracking/NQueen.js
index d76f232125..4b830dc73b 100644
--- a/Backtracking/NQueen.js
+++ b/Backtracking/NQueen.js
@@ -36,7 +36,6 @@ class NQueen {
 
   solve (col = 0) {
     if (col >= this.size) {
-      this.printBoard()
       this.solutionCount++
       return true
     }
diff --git a/Bit-Manipulation/BinaryCountSetBits.js b/Bit-Manipulation/BinaryCountSetBits.js
index 3fcb9d619c..60ae791231 100644
--- a/Bit-Manipulation/BinaryCountSetBits.js
+++ b/Bit-Manipulation/BinaryCountSetBits.js
@@ -13,5 +13,4 @@ function BinaryCountSetBits (a) {
   return a.toString(2).split('1').length - 1
 }
 
-// Run `binary_and` Function to find the binary and operation
-console.log(BinaryCountSetBits(251))
+export { BinaryCountSetBits }
diff --git a/Ciphers/Atbash.js b/Ciphers/Atbash.js
index 5f43737497..8ab7105fe2 100644
--- a/Ciphers/Atbash.js
+++ b/Ciphers/Atbash.js
@@ -23,7 +23,8 @@ function Atbash (message) {
   }
   return decodedString
 }
-// Atbash Example
-const encryptedString = 'HELLO WORLD'
-const decryptedString = Atbash(encryptedString)
-console.log(decryptedString) // SVOOL DLIOW
+
+export { Atbash }
+
+// > Atbash('HELLO WORLD')
+// 'SVOOL DLIOW'
diff --git a/Ciphers/CaesarsCipher.js b/Ciphers/CaesarsCipher.js
index 00bf1f1c1b..20e40c1ec4 100644
--- a/Ciphers/CaesarsCipher.js
+++ b/Ciphers/CaesarsCipher.js
@@ -29,8 +29,7 @@ function rot13 (str) {
   return response.join('')
 }
 
-// Caesars Cipher Example
-const encryptedString = 'Uryyb Jbeyq'
-const decryptedString = rot13(encryptedString)
+export { rot13 }
 
-console.log(decryptedString) // Hello World
+// > rot13('Uryyb Jbeyq')
+// 'Hello World'
diff --git a/Ciphers/KeyFinder.js b/Ciphers/KeyFinder.js
index 1a4059e335..add581f65b 100644
--- a/Ciphers/KeyFinder.js
+++ b/Ciphers/KeyFinder.js
@@ -44,15 +44,11 @@ function keyFinder (str) { // str is used to get the input of encrypted string
         for (let w = 0; w < wordBank[i].length; w++) {
           outStrElement += outStr[s + w]
         }
-
-        // console.log( k + outStrElement + wordBank[i] );//debug
-
         // this part need to be optimize with the calculation of the number of occurrence of word's probabilities
         // linked list will be used in the next stage of development to calculate the number of occurrence of the key
         if (wordBank[i] === outStrElement) {
           return k // return the key number if founded
         }
-
         outStrElement = '' // reset the temp word
       } // end for ( let i=0; i < wordBank.length; i++)
     }
@@ -145,4 +141,7 @@ function caesarCipherEncodeAndDecodeEngine (inStr, numShifted) {
   return outStr
 }
 
-console.log('Testing: ' + keyFinder('test')) // returns 0
+export { keyFinder }
+
+// > keyFinder('test')
+// 0
diff --git a/Ciphers/ROT13.js b/Ciphers/ROT13.js
index 24eeacf8e1..e644b20283 100644
--- a/Ciphers/ROT13.js
+++ b/Ciphers/ROT13.js
@@ -3,7 +3,7 @@
  * @param  {String} text - string to be encrypted
  * @return {String} - decrypted string
  */
-const transcipher = (text) => {
+const ROT13 = (text) => {
   const originalCharacterList = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
   const toBeMappedCharaterList = 'NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm'
   const index = x => originalCharacterList.indexOf(x)
@@ -11,11 +11,7 @@ const transcipher = (text) => {
   return text.split('').map(replace).join('')
 }
 
-(() => {
-  const messageToBeEncrypted = 'The quick brown fox jumps over the lazy dog'
-  console.log(`Original Text = "${messageToBeEncrypted}"`)
-  const rot13CipheredText = transcipher(messageToBeEncrypted)
-  console.log(`Ciphered Text = "${rot13CipheredText}"`)
-  const rot13DecipheredText = transcipher(rot13CipheredText)
-  console.log(`Deciphered Text = "${rot13DecipheredText}"`)
-})()
+export { ROT13 }
+
+// > ROT13('The quick brown fox jumps over the lazy dog')
+// 'Gur dhvpx oebja sbk whzcf bire gur ynml qbt'
diff --git a/Ciphers/VigenereCipher.js b/Ciphers/VigenereCipher.js
index 68ef3e85a0..800c3fdd94 100644
--- a/Ciphers/VigenereCipher.js
+++ b/Ciphers/VigenereCipher.js
@@ -71,8 +71,11 @@ function decrypt (message, key) {
   return result
 }
 
-const messageEncrypt = encrypt('Hello World!', 'code')
-console.log(messageEncrypt) // "Jhpnr Yrvng!"
+export { encrypt, decrypt }
 
-const messageDecrypt = decrypt('Jsopq Zstzg!', 'code')
-console.log(messageDecrypt) // "Hello World!"
+
+// > encrypt('Hello World!', 'code')
+// 'Jsopq Zstzg!'
+
+// > decrypt('Jsopq Zstzg!', 'code')
+// 'Hello World!'
diff --git a/Ciphers/XORCipher.js b/Ciphers/XORCipher.js
index 898b200dd6..2ee8205fbf 100644
--- a/Ciphers/XORCipher.js
+++ b/Ciphers/XORCipher.js
@@ -20,7 +20,13 @@ function XOR (str, key) {
   return result
 }
 
-const encryptedString = XOR('test string', 32)
-console.log('Encrypted: ', encryptedString)
-const decryptedString = XOR(encryptedString, 32)
-console.log('Decrypted: ', decryptedString)
+export { XOR }
+
+
+// Nb: Node REPL might not output the null char '\x00' (charcode 0)
+
+// > XOR('test string', 32)
+// 'TEST\x00STRING'
+
+// > XOR('TEST\x00STRING', 32)
+// 'test string'