Question

** C++ LANGUAGE **

Write a function that will implement each Fibonacci number with the help of an integer array of size 100 (elements of this array will be digits of the Fibonacci number).

When the function is called to find , it will calculate all Fibonacci numbers from to using the basic formula . To add two Fibonacci numbers, the function will add elements of two arrays corresponding to and and store their sums in the array corresponding to . (You are NOT supposed to store ALL arrays.)

Write a program that will calculate Fibonacci numbers containing up to 100 digits. Display the biggest Fibonacci number that has less than 100 digits. Make sure that your program will display the error message when a Fibonacci number has 100 digits or more.

Answer 1

//C++ program

#include <iostream>
using namespace std;

class long_number {
static const int max_digits = 100;
int number[max_digits];
int size;

public:
   long_number(){
       size = 0;
       for (int i = 0; i < max_digits; i++) {
               number[i] = 0;
        }
   }
   long_number(string input){
       size = input.length() ;
       for (int i = 1; i <= size; i++)
           number[max_digits- i] = (int)input[size - i] - (int)'0';
  
   }
long_number operator+(long_number rhs) {
           int carry =0;
           int i = max_digits -1;
           long_number ob;
           for (; i >= max_digits - max(size, rhs.size); i-- ) {
                   int sum = number[i] + rhs.number[i] + carry;
                   ob.number[i] = sum % 10;
                   carry = sum / 10;
               }
           ob.number[i] = carry;
           ob.size = max(size, rhs.size);
           if (carry > 0)ob.size++;
           return ob;
   }
   void print(){
       for (int i = max_digits - size ; i < max_digits; i++) {
       cout << number[i];
       }
       cout << endl;
   }
  
   int length(){
       return size;
   }

};

int main(){
   long_number a,c;
   long_number b("1");
  
   while(b.length()<=100){
       c = a+b;
       a=b;
       b=c;
   }
   a.print();
   return 0;
}