标题：请问为什么我的排序有问题？

#include <iostream>
#include <Windows.h>
using namespace std;
int main()
{
    BOOL WINAPI SetConsoleTitle(
        __in LPCTSTR lpConsoleTitle
    );
    SetConsoleTitle(L"谁考了第k名？");
    system("color F3");
    int value_person_sum;
    int value_look_person;
    cout << "请输入人数和需要查找的人！";
    cin >> value_person_sum >> value_look_person;
    int* value_student_number = new int[value_person_sum];
    double* value_student_grade = new double[value_person_sum];
    for (int i = 0; i < value_person_sum; i++)
    {
        cout << "第" << i + 1 << "名同学的学号和成绩：";
        cin >> value_student_number[i] >> value_student_grade[i];
    }
    cout << "输入完成！" << endl;
    Sleep(1000);
    for (int i = 0; i < value_person_sum; i++)
    {
        for (int j = i; j < value_person_sum; j++)
        {
            if (value_student_grade[j] > value_student_grade[i])
            {
                double temp = value_student_grade[j];
                value_student_grade[j] = value_student_grade[i];
                value_student_grade[i] = temp;
                int temp1 = value_student_number[j];
                value_student_number[j] = value_student_number[i];
                value_student_number[i] = temp1;
            }
        }
    }
    cout << "学号是：" << value_student_number[value_look_person] << "\n成绩是：" << value_student_grade[value_look_person] << endl;
    system("pause");
    system("cls");
    return 0;
}

请问我的循环哪里有问题啊？

    for (int i = 0; i < value_person_sum - 1; i++)
    {
        for (int j =0; j < value_person_sum - i - 1; j++)
        {
            if (value_student_grade[j] > value_student_grade[j+1])
            {
                double temp = value_student_grade[j];
                value_student_grade[j] = value_student_grade[j+1];
                value_student_grade[j+1] = temp;
                int temp1 = value_student_number[j];
                value_student_number[j] = value_student_number[j+1];
                value_student_number[j+1] = temp1;
            }
        }
    }