Question

I am working on a CSV file that I got from yahoo finance, which has information about the prices on the stock of AAPL. I am trying to display the first five greatest percent change that increased the most of that file.

for the percent change, I used:

s[x].percent_change = (s[x].adj_close2 - s[x].open2) / s[x].open2 * 100;

as my formula, which worked.

then I coded this:

    double original = s[0].percent_change;
    int maximum = 0;
    //Loop that computes the stock whose percentage change increased the most
    for (int i = 0; i < lines; i++) {

        if (s[i].percent_change > original) {
            original = s[i].percent_change;
            maximum = i;
        }

    }
    cout << "\n\nThe greatest percent change is the date: " << endl;
    cout << s[maximum].date << endl;
    cout << s[maximum].adj_close << endl;
    cout << s[maximum].percent_change << endl;

which again, worked, to get the stock whose percentage change increased the most

but the thing is, I cannot figure out what to do next after this.

How could I get the other four greatest results of the CSV file? I tried modifying the loop and adding another loop, but those loops did not work.

I am still learning c++, please be as simple as you can.

Answer 1

我认为这应该有效。但是，这是一种幼稚的方法。

double original[5];
for (int i = 0; i <5; i++){ #save the first 5 entries
    original[i] = s[i].percent_change;
}
int maximum[5] = {0,1,2,3,4};
//Loop that computes the stock whose percentage change increased the most
for (int i = 5; i < lines; i++) { #we can ignore the first 5 lines here
    for (int j = 0; j < 5 ; j++) {
        if (s[i].percent_change > original[j]) {
            original[j] = s[i].percent_change;
            maximum[j] = i;
            break;
        }
    }

}

请注意，如果s中的元素少于5个，则会失败。

Answer 2

C ++ STL中有排序方法。因此，使用它会更好。这是示例。

#include <algorithm>
#include <vector>

struct Row {
    float percent_change;
};

bool compareRow(const Row& a, const Row& b) {
    return a.percent_change > b.percent_change;
}

sort(s.begin(), s.end(), compareRow);
for (int i=0; i<5; i++) {
    cout << s[i].percent_change << endl;
}

也许最好检查一下此页面 https://www.geeksforgeeks.org/sorting-a-vector-in-c/

Get the first five greatest results in an array of vector

2 个答案: