c++ - 接收 0xC0000005 : Access violation reading location storing new pointer in pointer array

Question

我正在编写一个基本的 Asteroids 程序，使用 SFML 图形库，并且在调试程序时收到错误/崩溃。只有当我试图通过空格键从我的飞船发射一枚 “光子鱼雷” 时才会发生这种情况。这是代码片段。

//check for keypress

        if (event.type == sf::Event::KeyPressed && event.key.code == sf::Keyboard::Space) {
            for (int index = 0; index < MAX_PHOTONS; index++) {
                photons[index] = new SpaceObject(PHOTON_TORPEDO, PHOTON_RADIUS, ship->getLocation(), ship->getVelocity(), ship->getAngle())
                photons[index]->applyThrust(PHOTON_SPEED);
                std::cout << "LAUNCHING TORPEDO\n";
            }
        }

    // update game objects ------------------------------------------
     ship->updatePosition();

     for (int index = 0; index < ARRAY_SIZE; index++) {
         if (&asteroids[index] != NULL) {
             asteroids[index]->updatePosition();
         }
     }

     for (int index = 0; index < MAX_PHOTONS; index++) {
         if (&photons[index] != NULL) {
             photons[index]->updatePosition();
         }
     }


    // draw new frame ------------------------------------------------
    window.clear();
    window.draw(background);

    for (int index = 0; index < ARRAY_SIZE; index++) {
        if (&asteroids[index] != NULL) {
            asteroids[index]->draw(window);
        }
    }

    for (int index = 0; index < MAX_PHOTONS; index++) {
        if (&photons[index] != NULL) {
            photons[index]->draw(window);
        }
    }

运行代码会导致即时崩溃，调试结果为:

Unhandled exception at 0x00311746 in polygons2.exe: 0xC0000005: Access violation reading location 0x00000018.

我认为错误出在按键事件上。

Answer 1

您的代码有拼写错误。不要使用引用运算符访问对象引用。小行星和光子的元素是对应对象的地址。

 for (int index = 0; index < ARRAY_SIZE; index++) {
     if (asteroids[index] != NULL) {
         asteroids[index]->updatePosition();
     }
 }

 for (int index = 0; index < MAX_PHOTONS; index++) {
     if (photons[index] != NULL) {
         photons[index]->updatePosition();
     }
 }


// draw new frame ------------------------------------------------
window.clear();
window.draw(background);

for (int index = 0; index < ARRAY_SIZE; index++) {
    if (asteroids[index] != NULL) {
        asteroids[index]->draw(window);
    }
}

for (int index = 0; index < MAX_PHOTONS; index++) {
    if (photons[index] != NULL) {
        photons[index]->draw(window);
    }
}