How to preserve the values of a CSV file column in an array, so that we can use the array outside the loop in C++?

Question

I have read a csv file in string format using getline() function, then to store the marks column value in an integer type array I used stringstream. Then using a for loop I stored the first 10 marks in an array.

But when I am printing the values of the array outside of the loop from which we are reading the values of the CSV file it prints 0 for all marks and not retaining the values.

I tried making the array global and tried shifting the loop in which we are storing the marks in the array outside the loop in which we are reading the CSV file values but when i did this only the last value is getting print.

So, I want the values to get preserved outside the loop of reading CSV file such that we can use the array through out the program. enter image description here

int main()
{
    sorting obj;
    int arr1[10];
    ifstream o1("student.csv");
    if(!o1.is_open()) cout<<"error";
    string serialno;
    string name;
    string marks;
    string age;
    int du;

    for(int i=0; i<10; i++)
    {
        getline(o1, serialno,',');
        getline(o1, name,',');
        getline(o1, marks,',');
        getline(o1, age, '\n');
        //cout<<"student name :"<<name<<"\n";

        stringstream geek(marks);
        int marks1;
        geek >> marks1;

        for(int j = 0; j < 1; j++)
        {
            arr[j] = marks1;
            du = marks1;
        }

        for(int j = 0; j < 1; j++)
        {
            cout<<"test";
            cout<<arr[j]<<" - ";
        }
    }

    for(int c=0; c<10; c++)
    {
        cout<<arr[c]<<" ";
    }