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.
Official link: https://projecteuler.net/problem=2
Clearly all we need to do is generate the fibonacci numbers less than 4 million and sum all those that are even.
There are 2 tricks:
(1) n % 2 == 0 will return true if n is divisible by 2, which is essential an odd or even checker
(2) The simplest code for computing fibonnaci numbers goes as follows:
f1 = 1 #Initialize f1
f2 = 1 #Initialize f2
while True:
fn = f2 + f1 #Standard fibonacci equation
(Add condition for when you want it to stop)
f1 = f2 #Now we re-assign f1 to be our old f2
f2 = fn #Similarly we re assign f2 to be our new fn
becuase we are still in the while loop our new fn = f2 + f1 will take the updated values of f1 and f2
Enter a number (yourinput)
Code will output the answer from 1 to yourinput