Не пойму как записать условие Ball.deltaTime >= 10.f в функции remove_it для вектора Balls из структур Ball? (строка: int iterator = remove_if(balls.begin(), balls.end(), ball.lifeTime >= 10.f); в функции update()). Компилятор пишет ошибку:

[ 50%] Building CXX object CMakeFiles/workshop2.6.dir/main.obj D:\cpp\Projects\labs\workshop2\workshop2.6\main.cpp: In function 'void update(std::vector<Ball>&, float)': D:\cpp\Projects\labs\workshop2\workshop2.6\main.cpp:271:58: error: 'ball' was not declared in this scope      int iterator = remove_if(balls.begin(), balls.end(), ball.lifeTime >= 10.f);                                                           ^~~~ D:\cpp\Projects\labs\workshop2\workshop2.6\main.cpp:271:58: note: suggested alternative: 'balls'      int iterator = remove_if(balls.begin(), balls.end(), ball.lifeTime >= 10.f);                                                           ^~~~                                                           balls mingw32-make.exe[2]: *** [CMakeFiles\workshop2.6.dir\build.make:63: CMakeFiles/workshop2.6.dir/main.obj] Error 1 mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:67: CMakeFiles/workshop2.6.dir/all] Error 2 mingw32-make.exe: *** [Makefile:83: all] Error 2    #include <SFML/Graphics.hpp> #include <SFML/System.hpp> #include <SFML/Window.hpp> #include <vector> #include <cmath> #include <iostream> #include <string> #include <set> #include <random> #include <ctime>  using namespace std; using namespace sf;   constexpr unsigned BALLS_COUNT = 4; const string WINDOW_TITLE = "Moving balls"; static const sf::Color BACKGROUND_COLOR = sf::Color(0, 0, 0); constexpr unsigned WINDOW_WIDTH = 800; constexpr unsigned WINDOW_HEIGHT = 600;  struct Colr {     int red;     int green;     int blue;      bool operator<(const Colr& curr) const     {         if (red < curr.red)         {            return true;         }         else if (red == curr.red)         {             if (green < curr.green)             {                 return true;             }             else if (green == curr.green)             {                 return blue < curr.blue;             }         }          return false;     } };  struct Ball {     CircleShape shape;     Vector2f offset;     float lifeTime;     };  struct PRNG {     std::mt19937 engine; };  void initGenerator(PRNG&); size_t random_index(PRNG&, int); // Генерирует индекс в диапазоне [0, size) bool checkBGColor(Colr&); Colr initColor(PRNG, set<Colr>&); float setBallPosition(float, float); void initNewBall(PRNG, vector<Ball>&, Ball&, set<Colr>&); void pollEvents(RenderWindow&, PRNG, vector<Ball>&, Ball&, set<Colr>&); float length(const Vector2f&); float distance(const Ball&, const Ball&); float dot(const Vector2f&, const Vector2f&); float sqr(float); Vector2f getSpeedAfterStrike(const Ball&, const Ball&); void update(vector<Ball>&, float); void redrawFrame(RenderWindow&, vector<Ball>&); void initDefaultPlayGround(PRNG, vector<Ball>&, Ball&, set<Colr>&); void init(PRNG, set<Colr>&, vector<Ball>&, Ball&);  int main() {     Clock clock;     ContextSettings settings;     RenderWindow window(VideoMode({WINDOW_WIDTH, WINDOW_HEIGHT}), WINDOW_TITLE, Style::Default, settings);     vector<Ball> balls(BALLS_COUNT);     PRNG generator;     Ball ball;     set<Colr> isColrs;       initGenerator(generator);     init(generator, isColrs, balls, ball);      while (window.isOpen())     {         float deltaTime = clock.restart().asSeconds();         pollEvents(window, generator, balls, ball, isColrs);         update(balls, deltaTime);         redrawFrame(window, balls);     } }   void initGenerator(PRNG& generator) {     // Используем время с 1 января 1970 года в секундах как случайное зерно     const unsigned seed = unsigned(std::time(nullptr));     generator.engine.seed(seed); }  size_t random_index(PRNG& generator, int size) {     // Создаём распределение     std::uniform_int_distribution<int> distribution(0, size - 1);      // Вычисляем псевдослучайное число: вызовем распределение как функцию,     //  передав генератор произвольных целых чисел как аргумент.     return distribution(generator.engine); }  bool checkBGColor(Colr& colr) {     if((colr.red != BACKGROUND_COLOR.r) && (colr.green != BACKGROUND_COLOR.g) && (colr.blue != BACKGROUND_COLOR.b))     {         return 1;     }         else     {         return 0;     }      }  Colr initColor(PRNG generator, set<Colr>& isColrs) {     Colr colr;     colr.red = random_index(generator, 256);     colr.green = random_index(generator, 256);     colr.blue = random_index(generator, 256);     if(isColrs.empty() || (isColrs.find(colr) == isColrs.end()) && checkBGColor(colr))     {         isColrs.insert(colr);         return colr;     }     else     {         return initColor(generator, isColrs);             } }  float setBallPosition(float left, float right) {     return (left - right);  }  void initNewBall(PRNG generator, vector<Ball>& balls, Ball& ball, set<Colr>& isColrs) {     const float currSize = 40;      ball.offset.x = random_index(generator, 250);     ball.offset.y = random_index(generator, 250);     ball.lifeTime = 0.f;     ball.shape.setRadius(currSize);     Colr colr = initColor(generator, isColrs);     ball.shape.setFillColor(sf::Color(colr.red, colr.green, colr.blue));     ball.shape.setPosition(random_index(generator, setBallPosition(WINDOW_WIDTH, ball.shape.getRadius())), random_index(generator, setBallPosition(WINDOW_HEIGHT, ball.shape.getRadius())));         ball.shape.setOrigin(ball.shape.getRadius(), ball.shape.getRadius());     balls.insert(balls.end(), ball);      for (size_t fi = 0; fi < balls.size(); ++fi)     {         for (size_t si = fi + 1; si < balls.size(); ++si)         {             Ball& first = balls[fi];             Ball& second = balls[si];             while((distance(first, second) <= (first.shape.getRadius() + second.shape.getRadius())) || (balls.at(si).shape.getPosition().x <= balls.at(si).shape.getRadius()) || (balls.at(si).shape.getPosition().y <= balls.at(si).shape.getRadius()))             {                 balls.at(si).shape.setPosition(random_index(generator, setBallPosition(WINDOW_WIDTH, balls.at(si).shape.getRadius())), random_index(generator, setBallPosition(WINDOW_HEIGHT, balls.at(si).shape.getRadius())));                 balls.at(si).shape.setOrigin(balls.at(si).shape.getRadius(), balls.at(si).shape.getRadius());             }         }     } }  void pollEvents(RenderWindow& window, PRNG generator, vector<Ball>& balls, Ball& ball, set<Colr>& isColrs) {     Event event{};     while (window.pollEvent(event))     {         switch (event.type)         {         case Event::Closed:             window.close();             break;         case Event::MouseButtonReleased:             if(event.mouseButton.button == sf::Mouse::Left)             {                 initNewBall(generator, balls, ball, isColrs);                 }                 break;             default:             break;           }     } }  float length(const Vector2f& value) {     return std::hypot(value.x, value.y); }  float distance(const Ball& ball, const Ball& curr) {     return length(ball.shape.getPosition() - curr.shape.getPosition()); }   float dot(const Vector2f& left, const Vector2f& right) {     return left.x * right.x + left.y * right.y; }  float sqr(float value) {     return value * value; }  Vector2f getSpeedAfterStrike(const Ball& first, const Ball& second) {     const Vector2f deltaSpeed = first.offset - second.offset;     const Vector2f deltaPos = first.shape.getPosition() - second.shape.getPosition();     return first.offset - deltaPos * (dot(deltaSpeed, deltaPos) / sqr(length(deltaPos))); }  void update(vector<Ball>& balls, float deltaTime) {     constexpr float MAX_DELTA_TIME = 0.01f;     deltaTime = std::min(deltaTime, MAX_DELTA_TIME);      for (auto& ball: balls)     {         // TODO: extract variable ball.shape.getPosition()         // TODO: extract variable ball.shape.getRadius()         if ((ball.shape.getPosition().x >= WINDOW_WIDTH - ball.shape.getRadius()) || (ball.shape.getPosition().y >= WINDOW_HEIGHT - ball.shape.getRadius())         || (ball.shape.getPosition().x <= ball.shape.getRadius()) || (ball.shape.getPosition().y <= ball.shape.getRadius()))         {             ball.offset = -ball.offset;         }     }      for (size_t fi = 0; fi < balls.size(); ++fi)     {         for (size_t si = fi + 1; si < balls.size(); ++si)         {             Ball& first = balls[fi];             Ball& second = balls[si];             if(distance(first, second) <= (first.shape.getRadius() + second.shape.getRadius()))             {                   const Vector2f newFirstSpeed = getSpeedAfterStrike(first, second);                 const Vector2f newSecondSpeed = getSpeedAfterStrike(second, first);                 first.offset = newFirstSpeed;                 second.offset = newSecondSpeed;             }         }     }      for (auto& ball: balls)     {         ball.shape.move(ball.offset * deltaTime);         ball.lifeTime += deltaTime;     }      **int iterator = remove_if(balls.begin(), balls.end(), ball.lifeTime >= 10.f);** }  void redrawFrame(RenderWindow& window, vector<Ball>& balls) {     window.clear(BACKGROUND_COLOR);     for (auto& ball: balls)     {         window.draw(ball.shape);             }     window.display(); }  void initDefaultPlayGround(PRNG generator, vector<Ball>& balls, Ball& ball, set<Colr>& isColrs) {     const vector<float> sizes = {         40,         40,         40,         40     };          for (int i = 0; i < BALLS_COUNT; ++i)     {         balls.at(i).offset.x = random_index(generator, 250);         balls.at(i).offset.y = random_index(generator, 250);         balls.at(i).lifeTime = 0.f;         balls.at(i).shape.setRadius(sizes.at(i));         Colr colr = initColor(generator, isColrs);         balls.at(i).shape.setFillColor(sf::Color(colr.red, colr.green, colr.blue));         balls.at(i).shape.setPosition(random_index(generator, setBallPosition(WINDOW_WIDTH, balls.at(i).shape.getRadius())), random_index(generator, setBallPosition(WINDOW_HEIGHT, balls.at(i).shape.getRadius())));             balls.at(i).shape.setOrigin(balls.at(i).shape.getRadius(), balls.at(i).shape.getRadius());          for (size_t fi = 0; fi < balls.size(); ++fi)         {             while((balls.at(fi).shape.getPosition().x <= balls.at(fi).shape.getRadius()) || (balls.at(fi).shape.getPosition().y <= balls.at(fi).shape.getRadius()))             {                 balls.at(fi).shape.setPosition(random_index(generator, setBallPosition(WINDOW_WIDTH, balls.at(fi).shape.getRadius())), random_index(generator, setBallPosition(WINDOW_HEIGHT, balls.at(fi).shape.getRadius())));                 balls.at(fi).shape.setOrigin(balls.at(fi).shape.getRadius(), balls.at(fi).shape.getRadius());             }              for (size_t si = fi + 1; si < balls.size(); ++si)             {                 Ball& first = balls[fi];                 Ball& second = balls[si];                 while((distance(first, second) <= (first.shape.getRadius() + second.shape.getRadius())) || (balls.at(si).shape.getPosition().x <= balls.at(si).shape.getRadius()) || (balls.at(si).shape.getPosition().y <= balls.at(si).shape.getRadius()))                 {                     balls.at(si).shape.setPosition(random_index(generator, setBallPosition(WINDOW_WIDTH, balls.at(si).shape.getRadius())), random_index(generator, setBallPosition(WINDOW_HEIGHT, balls.at(si).shape.getRadius())));                     balls.at(si).shape.setOrigin(balls.at(si).shape.getRadius(), balls.at(si).shape.getRadius());                 }             }         }     } }    void init(PRNG generator, set<Colr>& isColrs, vector<Ball>& balls, Ball& ball) {     initDefaultPlayGround(generator, balls, ball, isColrs); }