This cryptography technique is one of the earliest in history. Simply said, it replaces each character with another, k values down the alphabet. Let's consider the English alphabet; assuming k = 4, the following word is encrypted as follows: Word: "hello" 4 letters down the alphabet for "h" is "I", "e" is "i", “I" is “p" and "o" is "s". So, the encrypted word is "lipps". To decrypt it we need to go back 4 letters in the alphabet. A person who knows what k is can only decipher it back. But there are other methods that a Caesar cypher can be broken. Certain letters in English alphabet has a specific frequency in text. For example, usually the frequency of letter "e" is 12%. If one calculates the frequencies of each letter and finds that a certain letter has 12% frequency, then it is most probably a replacement of letter "e". In this case the value for k can easily be guessed and the cypher can be broken. You are going to apply that technique to an integer number of 5 digits. Create a .cpp file named encrypt.cpp. In this program, ask the user to enter a value for k. Then ask the user to enter a 5- digit integer. Encrypt the number using the digit alphabet "0123456789" and store it in another integer variable. Print the value of the encrypted integer. For example: If k is 3, then the number 25764 is encrypted as 58097. When you add 3 to each digit if it passes the value 9, apply a modulus 10 operation on it. Think of a similar solution when you decrypt. Then, create another file decrypt.cpp. Assume that k is already known. Ask the user to enter the k value and then a 5-digit integer. Then decrypt the value to the original. Sample output for encrypt.cpp Enter key value k: 3 Enter a 5-digit integer to encrypt: Encrypted value: 58097 25764 Sample output for decrypt.cpp Enter key value k: 3 Enter a 5-digit integer to decrypt: 58097 Decrypted value: 25764

How do I learn coding? I want to learn c++ but I don't know what to write. Like I know there is something called a while loop but what is it and what does it do? Do you know any books or websites which can help?

Hey thank you for your answer.  I would like to know the main C++ modules that I need to know/understand to complete this program myself. i.e (Classes, structures, arrays, strings...) Please let me know the exact modules so I can study them as soon as possible.   Thank you.

C++ What one topic did you learn about that was most noteworthy What was your favorite topic? What was your least favorite topic? Why?  What other topics (s) would you like to see covered in this course(c++)? What topic(s) would you like to see removed from the course?

Do type-checking methods have an impact on the reliability of programs?