Write a C code using the following scenario: [10] Press 1 for addition Press 2 for subtraction Press n for exit Sample Input: Enter 1st num: 3 Enter 2nd num: 4 Sample Output: Addition: 7 Press y to continue Press n to exit

Consider the following common task done repeatedly:• Read the next input (x = read())• If the input is not valid (valid(x)), exit the loop• Print the input read (print(x))• Repeat the loopUsing C++ syntax:Write the loop above using a pretest loop, posttest loop and a user-located loop control mechanism. From the three which one is more readable and why?

Programming language: Dr. Racket Write a function encode that consumes a string message. The function produces a string which is encrypted according the following procedure: Only the letters from the original message will be encrypted. Other characters such as spaces, punctuation, numeric digits, etc. are not included in the encrypted message at all. The encrypted message will only contain uppercase letters. Each letter will be replaced by the uppercase letter at the opposite end of the English alphabet.In other words, A or a will become Z, B or b will become Y, C or c will become X, ..., Z or z will become A. The encrypted message will have a single space separating each letter. You may assume that the letters in message are English letters only.   For example:  > (encode "Cat") "X Z G" > (encode "Is this correct?")  "R H G S R H X L I I V X G"