"C + +", "Fibonacci", seek the first few Fibonacci numbers.

First, a solution using addition is written in the header file whichfibonaccinumber.h . There is no verification that the input number is less than 0.

#ifndef whichfibonaccinumber_h_#define whichfibonaccinumber_h_typedef unsigned long long uint64;//abbreviated unsigned long long , because it is 64 bits, writing UInt64 (meaning: Unsigned int 64 bit)//max = = 18446744073709551615, try to ensure that no overflow. Another: the "General formula" solution needs to open square. UInt64 whichfibonaccinumber (int numbers) {    if (1 = = Number | | 2 = #)    {        return 1;//sequence number is 1 and 2 Fibonacci is 1, return 1< c4/>}    Else    {        UInt64 prev = 1;//Previous number        UInt64 next = 1;//after a number        uint64 result = prev + next;//final return results, first two Number add        int index = 3;//number of Fibonacci numbers, 3rd is 2 while (number!        = index)//check ordinal        {            prev = next;            Next = result;            Result + = prev;//more than 3 lines to do is to update the number, and to calculate the new number            ++index;//new number of the ordinal        } return        result;//return the result    }} #endif// Whichfibonaccinumber

Then the main program main.cpp, using a loop to continuously enter the sequence number. The validation of the input sequence number is also done here.

#include <iostream> #include "whichfibonaccinumber.h" int main () {    using Std::cout;    Using Std::cin;    Using Std::endl;    unsigned long long and 8 bytes 64 bits    cout << "number of Fibonacci numbers:";    int index;    while (CIN >> index)    {        if (index <= 0)        {            cout << "ordinal cannot be less than 1" << Endl;            Continue;        }        cout << "<< index <<" Fibonacci numbers are: ";        cout << whichfibonaccinumber (index) << Endl;        cout << "continue to seek the first few Fibonacci numbers, or enter any non-numeric characters to exit:";    }    return 0;}

Impression: Neglect The basic knowledge, do not do well today. For I have not entered the training institutions, the interview unit will pay more attention to the basis of the test.

"C + +", "Fibonacci", seek the first few Fibonacci numbers.