1. large Fibonacci numbers

I'm trying to calculate the largest Fib. number less than 100 digits long using the general formula: F(n) = F(n-1)+F(n-2). Need to store it in an array one digit per cell. I checked through the search option and I found one really relevant post. But this post is talking about a large number read from a file... I need to calculate it! I'm trying to gather my thoughts first, and my question is whether to conduct the calculation using digits as strings, just like I would read it from a file??? I am kind of lost how to start. Any hints how to start thinking about it?
Thanks.

2. Well, a quick calculation yields 83108245990870293529395578470112099370436902820065 1613859972830080739980541065544674812034151699525.

Step 1: Make a char or int array with 100 elements where each element is a digit, initialise it to one. eg. a[99] = 1;

Step 2: Make a second char or int array with 100 elements where each element is a digit, initialise it to one. eg. b[99] = 1;

Step 3: Make a third char or int array (c), and add a to b using manual arithmetic you learned in elementary school and store it in c.

Step 4: assign (copy) b to a, then assign c to b.

Step 5: go back to step 3 the desired number of times.

3. Oh, you mean like I would be adding two binary numbers with carry-on, but in the decimal system? OK, thanks, that's what was missing... So simple. Thanks.

4. Or, best of all, use this:
Code:
```struct digit {
unsigned n : 10;  /* 1024 combinations */
};```
And use n to hold 3 digits.