Не существует подходящей функции преобразования из "const std::string" в "double"

Всем привет,столкнулся с такой проблемой "Не существует подходящей функции преобразования из "const std::string" в "double"" в строчке 52.Как ее решить?И извините за плохо вставленный код,еще не научился правильно вставлять коды в этом сайте.

#include <iostream>
#include <string>
#include <fstream>
#include <algorithm>
using namespace std;
class Contingent {
protected:
string firstname, lastname;
int age;
public:
Contingent(string = "John", string = "Jones", int = 32);
~Contingent() = default;
void printClass()const;
};
class HeightSchool {
protected:
string name;
int departments;
public:
HeightSchool(string = "Brighton", int = 5);
~HeightSchool() = default;
void printClass()const;
double getPub()const;
};
class Bachelor :public Contingent, public HeightSchool {
string specialty;
int grade;
public:
Bachelor(string = "Chemist", int = 51);
~Bachelor() = default;
bool operator <(const Bachelor&);
friend istream& operator >>(istream&, Bachelor&);
friend ostream& operator <<(ostream&, const Bachelor&);
};
Contingent::Contingent(string f, string l, int a) :
firstname(f), lastname(l), age(a) {}

void Contingent::printClass()const {
cout << "Saxeli: " << firstname
    << "\nGvari: " << lastname
    << "\nAsaki: " << age << endl;
    }

    HeightSchool::HeightSchool(string n, int d) :
    name(n), departments(d) {}

   void HeightSchool::printClass()const {
    cout << "Dasaxeleba: " << name
    << "\nFakultetebis ricxvi: " << departments << endl;
    }
    double HeightSchool::getPub()const { return name; }

    Bachelor::Bachelor(string s, int g) :
    Contingent(), HeightSchool(), specialty(s), grade(g) {}

    bool Bachelor::operator <(const Bachelor& l) {
    return this->grade < l.grade;
    }

    istream& operator >>(istream& in, Bachelor& l) {
    return in >> l.firstname >> l.lastname
    >> l.age >> l.name >> l.departments
    >> l.specialty >> l.grade;
    }
    ostream& operator <<(ostream& out, const Bachelor& l) {
     return out << "Saxeli: " << l.firstname
    << "\nGvari: " << l.lastname
    << "\nAsaki: " << l.age
    << "\nDasaxeleba: " << l.name
    << "\nFakultetebis ricxvi: " << l.departments
    << "\nSpecialoba: " << l.specialty
    << "\nShefaseba: " << l.grade << endl;
       }

        void fillArray(Bachelor*, int&);
    void printArray(const Bachelor*, int&);
    void intoFile(const Bachelor*, int&);

    int main() {
     static Contingent C("Dustin", "Poirier", 32);
     C.printClass();
       cout << "--------------------" << endl;

        static HeightSchool H("Tonbridge", 4);
         H.printClass();
      cout << "--------------------" << endl;

        Bachelor* ptr = new(nothrow) Bachelor[1200];
         int realSize{ 0 };
      fillArray(ptr, realSize);
     sort(ptr, ptr + realSize, [](Bachelor& k, Bachelor& l) { return l < k; });
     printArray(ptr, realSize);

     intoFile(ptr, realSize);

      delete[] ptr;
      ptr = nullptr;
      }

      void fillArray(Bachelor* arr, int& n) {
        ifstream ifs("bachelor.txt");
        while (!ifs.eof()) {
            ifs >> arr[n++];
        }
        ifs.close();
        }

       void printArray(const Bachelor* arr, int& n) {
       for (int i = 0; i < n; ++i) {
    cout << arr[i];
    cout << "--------------------" << endl;
      }
     }

    void intoFile(const Bachelor* arr, int& n) {
ofstream ofs("report.txt");
ofs << "Yvelaze udidesi shefaseba:\n\n";
for (int i = 0; i < n; ++i) {
    ofs << arr[i];
    if ((arr + i)->getPub() != (arr + i + 1)->getPub()) {
        break;
    }
}
ofs << "--------------------" << endl;

ofs << "Yvelaze umciresi shefaseba:\n\n";
for (int i = n - 1; i >= 0; ++i) {
    ofs << arr[i];
    if ((arr + n - i)->getPub() != (arr + n - i - 1)->getPub()) {
        break;
    }
}
ofs << "--------------------" << endl;

int average = 0;
for (int i = 0; i < n; ++i) {
    average += (arr + i)->getPub();
}
average /= n;

int index = 0, dif = abs((arr)->getPub() - average);
for (int i = 1; i < n; ++i) {
    if (abs((arr + i)->getPub() - average) < dif) {
        index = i;
        dif = abs((arr + i)->getPub() - average);
    }
}
ofs << "Yvelaze axlos yvela bakalavris sashualo shefasebastan:\n\n";
ofs << arr[index];
ofs << "--------------------" << endl;
ofs.close();
}