#include <list>

    struct Grass {
        struct {
            int x, y;
        } position;
    };

    int main() {
        std::list<Grass*> grassList;
        for(int i=0;i<50;i++){
            for(int j=0;j<50;j++){
                auto g1 = new Grass;
                g1->position.x = i;
                g1->position.y = j;
                grassList.push_back(g1);
            }
        }
        // ...
        for (auto& g1: grassList) {
            delete g1;
        }
        grassList.clear();
    }