Question

我正在用C编写扫雷游戏。我希望能够玩不同大小和矿山数量的不同雷区的游戏我创建了这样的结构来描述我的数据：

typedef struct t_Place Place;

struct t_Place{
    unsigned numberOfMinesNear;
    int mine;
    int state;
};

typedef struct t_Minefield Minefield;

struct t_Minefield{
    int xSize;
    int ySize;
    unsigned minesNumber;
    Place **places; 
};

所以，现在我正在尝试初始化我的雷区。我做了以下事情：

void makeGame(Minefield *minefield, unsigned x, unsigned y, unsigned mines){
    int i, j;  
minefield->places = malloc(x * y * sizeof(Place));       
    for(i = 0; i < x; i++)
        for(j = 0; j < y; j++){
            minefield->places[i][j].mine = EMPTY;
            minefield->places[i][j].state = HIDDEN;
            minefield->places[i][j].numberOfMinesNear = 0;
        }

minefield->xSize = x;
    minefield->ySize = y;

    unsigned minesToPlace = mines;
    srand(time(NULL));
    while(minesToPlace > 0){
        i = rand() % x;
        j = rand() % y;

        if(minefield->places[i][j].mine)
            continue;

        minefield->places[i][j].mine = MINE;
        minesToPlace--;      
    }  
    minefield->minesNumber = mines;
    // here will be call of play(minefield) function to start the game
}

int main(){
    Minefield *gameField = (Minefield *) malloc(sizeof(Minefield));

    makeGame(gameField, DEFAULT_X, DEFAULT_Y, DEFAULT_MINES);

    // DEFAULT_X = DEFAULT_Y = DEFAULT_MINES =  10

    free(gameField);
    return 0;
}

我在makeGame函数的第一行代码中遇到了段错误。我做错了什么？我想动态地为我的雷区分配内存，而不是静态。

Answer 1

minefield->places = malloc(x * y * sizeof(Place));

上述内存分配可能是问题的根源，places是一个双星指针，因此必须有两个malloc()调用，一个用于分配行号**place指针，然后是另一个malloc()，以分配*place类型place指针的列数。

这是分配/初始化结构中包含的两个星形指针的SSCCE。

#include <stdio.h>
#include <stdlib.h>

#define ROW_SZ 5
#define COL_SZ 25

typedef struct demo{
char **str;
}demo;


int main()
{

demo *d = malloc( sizeof(demo) );

d->str = malloc(ROW_SZ * sizeof(char*) );             //d->str is assigned char**
  for ( i = 0; i < ROW_SZ; i++ )
        d->str[i] = malloc(COL_SZ * sizeof(char) );   //d-str[i] is assigned char*

// code here to use d->str[ROW_SZ][COL_SZ]

for ( i = 0; i < ROW_SZ; i++ )
  free(d->str[i]);


free(d->str);
free(d);

return 0;
}

Answer 2

我通常会看到分配的2D数组：

minefield->places = malloc(x * sizeof(Place *));       

for(i = 0; i < x; i++)
{
    minefield->places[i] = malloc(x * sizeof(Place));
}

试试这个，看看它是否会让你失误。

我的简单游戏中的内存分配

2 个答案: