Prioject Euler problem2 :Even Fibonacci numbers

问题描述：

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:

1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

C++实现：

#include <bits/stdc++.h>
using namespace std;
int main(){
long  f1 = 1;
long  f2 = 2;
long  f3 = 2;
long  sum = 0;
for (; f3 < 4000000 ;) {
if(f3 % 2 == 0){
sum += f3;
}
f3 = f1 + f2;
f1 = f2;
f2 = f3;
}

cout<< sum << endl;

return 0;
}

python 实现：

i = 1
j = 2
f = 2
sum = 0
max = 4E6
while f < max:
if f % 2 == 0:
sum += f
f = i + j
i = j
j = f

print(sum)