欧拉计划 第2题 By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

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.

斐波那契数列，找出不超过4百万的所有偶数项的累加和。

#include <stdio.h>
main()
{
  int i=1,j=2,sum=0;
   while(i<4000000 && j<4000000)
   {
     if(j%2==0) sum+=j;
     i=i+j;
     if(i%2==0) sum+=i;
     j=i+j;
   }
  printf("sum=%d",sum);
}