Question

I’m a relatively new java programmer and I’ve been tinkering around with this program for the better part of the day now and I’m still stuck; I was hoping that you could help me with this.

So the program is supposed to meet the following requirements:

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.

This is my code:

    //Generates Fibonacci sequence
    while (fibNum < 144)
    {
        int lastValue = (Integer) fibList.get(fibList.size()-1);
        int secondToLastValue = (Integer) fibList.get(fibList.size()-2);

        fibNum = secondToLastValue + lastValue;

        if (fibNum < 144)
        {
            fibList.add(fibNum);
        }

    //Picks out the even numbers from limitFibList
    for (int i = 0; i < fibList.size(); i++)
    {
        if ((Integer) fibList.get(i) % 2 == 0)
        {
            evenNumsFibList.add(fibList.get(i));
        }
    }

    //Sums up the total value of the numbers in the evenNumsFibList
    for (int i = 0; i < evenNumsFibList.size(); i++)
    {
        sum += (Integer) evenNumsFibList.get(i); 
    }

…and this is the output that I’m getting:

Fibonacci sequence list: [1, 2, 3]
Size of the Fibonacci list: 3
Even Numbers list: [2]
Total sum of even numbers: 2

Fibonacci sequence list: [1, 2, 3, 5]
Size of the Fibonacci list: 4
Even Numbers list: [2, 2]
Total sum of even numbers: 6

Fibonacci sequence list: [1, 2, 3, 5, 8]
Size of the Fibonacci list: 5
Even Numbers list: [2, 2, 2, 8]
Total sum of even numbers: 20

Fibonacci sequence list: [1, 2, 3, 5, 8, 13]
Size of the Fibonacci list: 6
Even Numbers list: [2, 2, 2, 8, 2, 8]
Total sum of even numbers: 44

Fibonacci sequence list: [1, 2, 3, 5, 8, 13, 21]
Size of the Fibonacci list: 7
Even Numbers list: [2, 2, 2, 8, 2, 8, 2, 8]
Total sum of even numbers: 78

Fibonacci sequence list: [1, 2, 3, 5, 8, 13, 21, 34]
Size of the Fibonacci list: 8
Even Numbers list: [2, 2, 2, 8, 2, 8, 2, 8, 2, 8, 34]
Total sum of even numbers: 156

Fibonacci sequence list: [1, 2, 3, 5, 8, 13, 21, 34, 55]
Size of the Fibonacci list: 9
Even Numbers list: [2, 2, 2, 8, 2, 8, 2, 8, 2, 8, 34, 2, 8, 34]
Total sum of even numbers: 278

Fibonacci sequence list: [1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
Size of the Fibonacci list: 10
Even Numbers list: [2, 2, 2, 8, 2, 8, 2, 8, 2, 8, 34, 2, 8, 34, 2, 8, 34]
Total sum of even numbers: 444

Fibonacci sequence list: [1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
Size of the Fibonacci list: 10
Even Numbers list: [2, 2, 2, 8, 2, 8, 2, 8, 2, 8, 34, 2, 8, 34, 2, 8, 34, 2, 8, 34]
Total sum of even numbers: 654

Obviously my while loop is contributing to my problems, but I don’t know how to fix it.

Would greatly appreciate your help,

Haque

Answer 1

Looks like you are missing the close brackets on the while loop. So the other for‘s are running within it.

So:

while (fibNum < 144)
    {
        int lastValue = (Integer) fibList.get(fibList.size()-1);
        int secondToLastValue = (Integer) fibList.get(fibList.size()-2);

        fibNum = secondToLastValue + lastValue;

        if (fibNum < 144)
        {
            fibList.add(fibNum);
        }
    }

    //Picks out the even numbers from limitFibList
    for (int i = 0; i < fibList.size(); i++)
    {...