Question

Hello I’m an amateur programmer, and to make it worse it has been a while since I’ve done any programming so I decided to refresh my memory with some easy Topcoder problems. The first one I did ended up being a segment fault, and right now that’s beyond what I can figure out for myself, can anyone help me understand where the segment fault came from. Here is the code.

vector<int> Bonuses (vector<int> points)
{
    int totalPoints = 0;
    for (int i = 0; i != points.size(); ++i)
    {
        totalPoints += points[i];
    }

    vector<int> percentage;
    int percentageLeft = 100;
    int truncatedPercentage;

    for (int i = 0; i != points.size(); ++i)
    {
        truncatedPercentage = points[i]/totalPoints;
        percentage.push_back(truncatedPercentage);
        percentageLeft -= truncatedPercentage;
    }
    for (int i = 1;i <= percentageLeft; ++i)
    {
        percentage[percentage.size() - i] += 1;
    }
    return percentage;


}

Answer 1

You have a logic error in your program. Change this:

truncatedPercentage = points[i]/totalPoints;

to this:

truncatedPercentage = points[i] * 100 / totalPoints;

Otherwise the percentage will be almost always 0, and the percentageLeft will be 100. That is why percentage[percentage.size() - i] += 1 is segfaulting as AndersK already found before me. The index is typically negative.

That said, I am uncertain on whether mixing pushbacks and direct assignments gives you the most readable code that you could have here.