C only thankyou!

- Write a program that receives an integer number from user and prints the all the multiples of 7 from 1 to the entered number, and also the average of all the printed numbers. If the number is negative, program should print a message indicating the negative numbers are not acceptable, and then repeats until a proper number is entered.

- Write a simple calculator program that stays in a loop, shows 5 options to user (0 for exit, 1 to 4 for four basic operations). Once a selection is made for an operation, it asks for two operands, performs the operation and shows the result, then goes back to the loop.

- Add a comment section describing the algorithm for each of the 2 parts