javascript - Euler #2 Fibonacci Javascript 函数在处理数字后只会返回零

Question

我编写了一个函数来解决 JavaScript 中的 Euler #2，将所有偶数斐波那契数相加到 4,000,000。然而，当我运行我的函数时，chrome 开发工具不断给我零作为答案。我不知道为什么。

function DoEverything() {
  oldnum = 0;
  num = 1;
  total = 0;
  result = addFibNumbers(num, oldnum);
  console.log(result);
} 
function addFibNumbers(num, oldnum) {
  while(num < 4000000) {
    if (num % 2 == 0) {
      newnum = num + oldnum;
      total += newnum;
      oldnum = num;
      num = newnum;
    }
  return total;
  }
}
DoEverything();

Answer 1

返回0的原因:

result = addFibNumbers(num, oldnum);//num=1,oldNum=0

//function
while(num < 4000000) { //num is 1, so it enters while
if (num % 2 == 0) {// 1 % 2 == 1, so skip this if
return total;// this ends the function, returning total=0 as nothing was changed

我猜你想这样做:

  while(num < 4000000) {
      newnum = num + oldnum;
      if (newnum % 2 == 0 && newnum < 4000000) {
          total += newnum;
      }
      oldnum = num;
      num = newnum;
  }
  return total;