To apply your skills in the implementation of prime number calculating algorithms.

In addition to the new skills required on previous projects, to successfully accomplish/perform this project, the listed resources/experiences need to be consulted/achieved:

• ability to make decisions (if statement)
• ability to iterate sections of code (for/while statement)

In mathematics, a prime number is a value that is only evenly divisible by 1 and itself; it has no other factors. Numbers that have divisibility/factors are known as composite numbers.

The number 6 is a composite value, as in addition to 1 and 6, it also has the factors of 2 and 3.

The number 17 is a prime number, as no numbers other than 1 and 17 can be evenly divided.

As of yet, there is no quick and direct way of determining the primality of a given number. Instead, we must perform a series of tests to determine if it fails primality (typically by proving it is composite).

This process incurs a considerable amount of processing overhead on the task, so much so that increasingly large values take increasing amounts of time. Often, approaches to prime number calculation involve various algorithms, which offer various benefits (less time) and drawback (more complex code).

Your task for this project is to implement 3 prime number programs:

1. brute force prime calculation
2. square root-optimized brute force calculation
3. a further optimized solution

It is your task to write the program that will use the above method to compute the requested one-, two-, or three-digit value against a multiplicand of 11 (without using any multiplication to obtain your result).

Your program should:

• obtain its input from STDIN.
  • input should be in the form of a single integer value
• determine from the input if it is a one-, two-, or three-digit number
• perform the correct algorithm against the input
• propagate any carries
• output the final value
  • you can display each digit individually, or combine them into one variable and display that (whichever you prefer)

Several operating behaviors are shown as examples.

A two digit value:

lab46:~/src/cprog/mbe0$ ./multby11
Enter value: 32
32 x 11 = 352
lab46:~/src/cprog/mbe0$ 

Next, a one digit value:

lab46:~/src/cprog/mbe0$ ./multby11
Enter value: 7
7 x 11 = 77
lab46:~/src/cprog/mbe0$ 

Finally, three digit value:

lab46:~/src/cprog/mbe0$ ./multby11
Enter value: 567
567 x 11 = 6237
lab46:~/src/cprog/mbe0$ 

The execution of the programs is short and simple- parse the input, do the processing, produce the output, and then terminate.

There will be an additional bonus point opportunity with this project, based on processing run-time of your optimized solution.

To successfully complete this project, the following criteria must be met:

• Code must compile cleanly (no warnings or errors)
• Output must be correct, and match the form given in the sample output above.
• Code must be nicely and consistently indented (you may use the indent tool)
• Code must utilize the algorithm(s) presented above:
  • primebrute.c must do the unoptimized brute force method
  • primesqrt.c must utilize the brute force method along with the square root trick (no other tricks)
  • primeopt.c is your attempt at optimizing the code, using whatever additional tricks (or enhancements to tricks) to further improve runtime.
• Code must be commented
  • have a properly filled-out comment banner at the top
    • be sure to include any compiling instructions
  • have at least 20% of your program consist of //-style descriptive comments
• Output Formatting (including spacing) of program must conform to the provided output (see above).
• Track/version the source code in a repository
• Submit a copy of your source code to me using the submit tool.

To submit this program to me using the submit tool, run the following command at your lab46 prompt:

$ submit cprog pnc0 primebrute.c primesqrt.c primeopt.c
Submitting cprog project "pnc0":
    -> primebrute.c(OK)
    -> primesqrt.c(OK)
    -> primeopt.c(OK)

SUCCESSFULLY SUBMITTED

You should get some sort of confirmation indicating successful submission if all went according to plan. If not, check for typos and or locational mismatches.