c++ - 我正在任意更改变量，出现“6011 取消引用空指针”的警告

Question

我的变量似乎是随机变化的。我唯一的线索是“6011 取消引用空指针”。我在 MSVS 上使用 C++ 和 allegro。

我尝试逐行浏览代码并在常见问题区域放置断点。实际上，在我将grabframe的参数从采用宽度和高度更改为采用精灵并使用其宽度和高度时，实际上可能会变得更糟。但即使在变化之前，变量也在随机变化

在我的标题中：

//define the sprite structure
typedef struct SPRITE{
    int dir, alive;
    int x, y;
    int width, height;
    int xspeed, yspeed;
    int xdelay, ydelay;
    int xcount, ycount;
    int curframe, maxframe, animdir;
    int framecount, framedelay;
}SPRITE;
SPRITE* player1spr;
BITMAP* player1[121];

在我的 C++ 文件中，其中包括主要内容：

//grabframe function
//takes sprites out of a sprite sheet and stores it in bitmaps
//parameters are:
//BITMAP* source: a bitmap that holds the sprite sheet
//SPRITE* sprite: the sprite that is going to use the frame
//int startx: the start x coordinate of the sprite sheet
//int starty: the start y coordinate of the sprite sheet
//int columns: the amount of columns the sprite sheet has
//int frame the frame thats being grabbed
BITMAP* grabframe(BITMAP* source, SPRITE* sprite, int startx, int starty, int columns, int frame) {
    //create temporary bitmap to hold the sprite
    BITMAP* temp = create_bitmap(sprite->width, sprite->height);
    //find the dimensions of a sprite given the properties of the sprite      sheet
    int tempx = startx + (frame % columns) * sprite->width;
    int tempy = starty + (frame / columns) * sprite->height;
    //blit the sprite onto the sheet
    blit(source, temp, tempx, tempy, 0, 0, sprite->width, sprite->height);
    return temp;
}

在我的主要：

player1spr = (struct SPRITE*)malloc(sizeof(SPRITE*));
player1spr->maxframe = 121;
player1spr->curframe = 0;
player1spr->width = 600;
player1spr->height = player1spr->width;

// create a bitmap for the player one character
temp1 = (BITMAP*)data[PLAYER1_BMP].dat;
for (player1spr->curframe = 0; player1spr->curframe < player1spr->maxframe; player1spr->curframe++) {
    player1[player1spr->curframe] = grabframe(temp1, player1spr, 0, 0, 11, player1spr->curframe);
}
destroy_bitmap(temp1);

像这样的错误：

Exception thrown at 0x0F81B605 (allegro-4.4.2-monolith-md.dll) in Assignment2 v2.exe: 0xC0000005: Access violation reading location 0x00000010.

我希望我的精灵变量保持不变，但它们会改变。

标签： c++visual-studionull-pointer