Description
Project 1:
Introduction: Cryptography is the science of making messages secure, of transforming readable
messages into unreadable messages and back again. Messages that are unreadable are called
ciphertext.
The process of turning plaintext into ciphertext is called encryption. The reverse
process of turning ciphertext into plaintext is called decryption. One of the easiest ways to
encrypt a message is to scramble the letters. For example the word “apple” could be randomly
transformed to “lapep” In fact there are 120 different possible arrangements of the word “apple.”
However, if the encryption algorithm randomly scrambles the letters, the task of the decryption
algorithm is hard. Encryption and decryption algorithms must work together in some agreed
upon way, with the encryption algorithm scrambling letters and the decryption algorithm
unscrambling them.
A transposition cipher is one way to scramble the letters of a message. The cipher separates the
message into two groups of characters: the first group composed of the even-numbered
characters and the second group composed of the odd-numbered characters.
To produce the
ciphertext, the cipher puts together both groups; placing the group of the even-numbered
characters first, followed by the group of odd-numbered characters. This encryption results in a
string with the characters shuffled to new positions.
1. Ask user to enter a string. Write a function that takes the string as a parameter,
encrypt the message as described above and returns the ciphertext. Then ask user
again if she/he wants to continue or not. Finally print all the original messages in
alphabetically ascending order.
Example:
Please enter a message: Fight, Matadors, for Tech!
The encrypted message is: ih,Mtdr,frTc!Fgt aaos o eh
Do you want to continue(Y/N)? Y
Please enter a message: Bear our banners far and wide.
The encrypted message is: erorbnesfradwd.Ba u anr a n ie
The original messages in alphabetical order are:
Bear our banners far and wide
Fight, Matadors, for Tech!
Project 2:
You will create an ATM menu specified below
1) Check balance
2) Make a Deposit
3) Make a Withdrawal
4) Change Password
5) Exit
Please type a number from 1 to 5 to select a menu item:
When a number is input by the user, you will print the string corresponding to the number and
execute the task as shown below in the list. The underlined entity is the user input for each
choice in the menu.
User entered 1
Execute Check balance
Balance is $ 153.80
User entered 2
Execute Make a Deposit
Enter amount to deposit: 54.77
New Balance is $ 208.57
User entered 3
Execute Make a Withdrawal
Enter amount to withdraw: 40.00
New Balance is $ 168.57
User entered 4
Execute Change Password
Enter new password: 99999999
New Password is “99999999”
User entered 5
Execute Exit
Terminating program
Have a nice day!
If the input number is 5, your program should terminate as shown above. Otherwise, after every
transaction is completed you would print a new line
Press any key to continue your transactions …
Your program will wait until user presses any key on the keyboard. After a key is pressed, your
program will display the menu as above and repeat the process above. Note in the process above,
when a number is not in 1 to 5, you will ignore the input.
You will use getchar() to consume and putchar() to print the character entered by the user
is a standard I/O (input/output) function with the following specification (slightly modified from
its original specification)
Internally you will create the following variables and any others to hold needed information.
1) MyAccount-Store a float number
2) Initialize MyAccount to 1000.00 as initial balance
3) Password – Store an integer of length 8 digits
4) Initialize Password to 12345678
5) Char variable/s to hold user input and key press.
6) When 1) is pressed you will display contents of MyAccount
7) Deposit increments MyAccount
8) Withdrawal decrements MyAccount
9) When 5 is pressed you must exit cleanly from the Program
Write pseudocode to solve the given problems.
Write C program to solve the above problems. Name your file Lab9_YourName.c
