C++ Implementation of Problem 2

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Includes

Solution

uint64_t p0002()
int main(int argc, char const *argv[])

Note

This function is only present in the Python test runner, or when compiling as a standalone program.

 1/*
 2Project Euler Problem 2
 3
 4Again, see Python implementation for a proof
 5
 6Problem:
 7
 8Each new term in the Fibonacci sequence is generated by adding the previous two
 9terms. By starting with 1 and 2, the first 10 terms will be:
10
111, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
12
13By considering the terms in the Fibonacci sequence whose values do not exceed
14four million, find the sum of the even-valued terms.
15*/
16
17#ifndef EULER_P0002
18#define EULER_P0002
19#include <stdint.h>
20#include <iostream>
21#include "include/macros.hpp"
22
23uint64_t EMSCRIPTEN_KEEPALIVE p0002() {
24    uint64_t answer = 0,
25    a = 1, b = 2, t;
26    while (b < 4000000) {
27        // odd (1, 3, 13, 55, ...)
28        // odd (1, 5, 21, 89, ...)
29        // even (2, 8, 34, 144, ...)
30        answer += b;
31        for (uint8_t z = 0; z < 3; z++) {
32            t = b;
33            b = a + b;
34            a = t;
35        }
36    }
37    return answer;
38}
39
40
41PROGRAM_TAIL(p0002)
42#endif

Tags: fibonacci-number, divisibility