C++ noob needs help :(

I thought about trying the Project Euler thing when you brought it up.

On the one hand, I like the programming part. If I didn't, then I put a lot of effort into getting a degree in something I hate (and got near-straight A's in it, too... bloody interface design :evil: )... :lol:

On the other hand, I don't do well with numbers (something that might baffle other programmers, and my math teachers in college). It took me several tries to finally understand algebra (high school, two math courses in the Navy, then it finally clicked in college... where I tutored math, too... :? ), and arithmetic can get me in trouble (9 * 7 != 16... I know it, I feel it, but it's even money if I actually write it correctly).

I'll ponder some more... I'm leaning towards "go for it," though. ;)

OrkHammer007

[QUOTE="HardQuor"]Yeah, that's way over my head :( I'll just consider my solution a good compromise between conciseness and elegance :PGabuEx

Well, it's actually not too conceptually difficult.  I probably just explained it badly.  There are two main concepts that need to be understood with what I was talking about:

1. First, there are prime numbers (numbers which are divisible by only 1 and itself), and there are composite numbers (numbers which are divisible by more than that).  Any composite number can be represented as a product of prime numbers (for example, 12 = 2 * 2 * 3).

2. Second, to say that x is divisible by y is to say that all prime factors of y are also prime factors of x.  For example, 12 is divisible by 4 because 12 = 2 * 2 * 3, while 4 = 2 * 2 - all prime factors of 4 are also prime factors of 12.

See if what I said makes any more sense in light of those two things (or tell me if the above also makes no sense).

What is over my head is conceptualizing it all in code. Although, i'm not really dedicating a lot of thought to it, admittedly :PHardQuor

...and I can tell you that it requires a fair bit more complex constructs than just ints and loops. :PGabuEx

[QUOTE="GabuEx"]...and I can tell you that it requires a fair bit more complex constructs than just ints and loops. :POrkHammer007

Well, problem 3 seems to be a lot simpler than i thought it would be. It asks for the largest prime number of 600 billion something. I've got the code to work on a smaller number, but unfortunately, i've run into the problem of my int data type not being able to contain the full 12 digits of the term. I've tried long ints, unsigned ints, and unsigned long ints. Anyone have a solution?HardQuor

[QUOTE="GabuEx"] Use a double.HardQuor

Include math.h and do (n / m == floor(n / m)) instead.  That's equivalent to (n % m == 0).

[QUOTE="HardQuor"][QUOTE="GabuEx"] Use a double.GabuEx

Include math.h and do (n / m == floor(n / m)) instead.  That's equivalent to (n % m == 0).

[QUOTE="GabuEx"]

[QUOTE="HardQuor"] I'd love to, but it won't let me use % with doubles :?HardQuor

Include math.h and do (n / m == floor(n / m)) instead.  That's equivalent to (n % m == 0).

[QUOTE="GabuEx"]

[QUOTE="HardQuor"] I'd love to, but it won't let me use % with doubles :?HardQuor

Include math.h and do (n / m == floor(n / m)) instead.  That's equivalent to (n % m == 0).

[QUOTE="HardQuor"][QUOTE="GabuEx"]

 

Include math.h and do (n / m == floor(n / m)) instead.  That's equivalent to (n % m == 0).

GabuEx

[QUOTE="OrkHammer007"]OK... I'm officially intrigued. The only thing I can think of is an array of primes, and looping through them to modulus the target number, and I have a feeling that's not it. :|GabuEx

Almost seems easier to take a piece of paper, work out the prime factors from 2-20, then grabbing a calculator and physically multiplying it together. ;)

Is it normal to feel stupid even though, in asking for it, i've already accepted that i don't know the answers to my problems? :? HardQuor

Just keep in mind that, the more you know, the more you can still learn. :D

(Like now... I realize that the cIass I took in Web Scripting is helping me deal with GS's posting quirks... :lol: )