Как инициализировать Vector <class>?

class pupil
{
public:
    string name;
    int mat;
    int inf;
    int lit;
};

for (int i = 0; i < 10; i++)
mas.push_back(0);

public: 
pupil(string _name = "", int _mat=0, int _inf=0, int _lit=0) : name(_name), mat(_mat), inf(_inf), lit(_lit) {};

mas.push_back(pupil("name", 2,3,4));

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
 
class people
{
    std::string name = "No name";
    int val1 = 0, val2 = 0, val3 = 0;
public:
    people() {}
    people(const char* name_, int n1, int n2, int n3) : name(name_) {
        val1 = n1; val2 = n2, val3 = n3;
    }
 
    void show() const {
        std::cout << "[" << name << "] (" << val1 << ", " << val2 << ", " << val3 << ")\n";
    }
 
    int sum() const { return val1 + val2 + val3; }
};
 
struct comparer : std::binary_function<int, int, bool> {
    bool operator ()(const people& lhs, const people& rhs) {
        return lhs.sum() < rhs.sum();
    }
};
 
int main()
{
    std::vector<people> v;
    v.emplace_back("Vasa", 5, 4, 3);
    v.emplace_back();
    v.emplace_back("Sveta", 2, 4, 6);
    v.emplace_back("Lena", 5, 10, 6);
    v.emplace_back("Masha", 2, 1, 4);
    v.emplace_back("Vova", 3, 11, 2);
 
    for (auto& p : v) p.show();
 
    //сортируем по сумме.
    //способ 1(самый простой):
    std::sort(v.begin(), v.end(), [](const people& p1, const people& p2) {
        return p1.sum() < p2.sum();
    });
 
    std::cout << "\n\n";
    for (auto& p : v) p.show();
 
    //способ 2:
    using namespace std::placeholders;
    std::sort(v.begin(), v.end(), std::bind(std::greater<int>(),
                                  std::bind(&people::sum, _1),
                                  std::bind(&people::sum, _2) ));
 
    std::cout << "\n\n";
    for (auto& p : v) p.show();
 
    //способ 3:
    std::sort(v.begin(), v.end(), comparer());
 
    std::cout << "\n\n";
    for (auto& p : v) p.show();
 
    std::cout << "\nDone." << "\n";
    return 0;
}