Implements a C++ class that allows you to create integers of arbitrary size. This data structure can be handy when you want to avoid overflow and has proven a handy way to solve project Euler [1] problems.
The following code snippet illustrates basic usage:
#include <iostream>
#include "helper/big_number.cpp"
using namespace std;
int main() {
BigNumber fn(1000, 1);
BigNumber fn_minus_1(1000, 1);
long count = 3;
// Compute successive Fibonacci sequence values until one is
// found with 1000 digits. Report the result.
while (1)
{
fn = fn - fn_minus_1;
fn_minus_1 = fn + fn_minus_1;
fn = fn_minus_1 * 2 - fn;
if (fn.get_digit(999) > 0)
break;
count++;
}
fn.print();
cout << "The " << count << " term of the fibonacci sequence is the first to contain at least 1000 digits." << endl;
return 0;
}
If we add this code to the file fib.cpp compile then run we get:
~rfaulk$ g++ -Wall fib.cpp -o fib
~rfaulk$ ./fib
1070066266382758936764980584457396885083683896632151665013235203375314520604694040621889147582489792657804694888177591957484336466672569959512996030461262748092482186144069433051234774442750273781753087579391666192149259186759553966422837148943113074699503439547001985432609723067290192870526447243726117715821825548491120525013201478612965931381792235559657452039506137551467837543229119602129934048260706175397706847068202895486902666185435124521900369480641357447470911707619766945691070098024393439617474103736912503231365532164773697023167755051595173518460579954919410967778373229665796581646513903488154256310184224190259846088000110186255550245493937113651657039447629584714548523425950428582425306083544435428212611008992863795048006894330309773217834864543113205765659868456288616808718693835297350643986297640660000723562917905207051164077614812491885830945940566688339109350944456576357666151619317753792891661581327159616877487983821820492520348473874384736771934512787029218636250627816
The 4781 term of the fibonacci sequence is the first to contain at least 1000 digits.