CrtIsValidHeapPointer错误，当试图释放链表的元素

我的程序崩溃与无效堆指针相关的错误。在第一个函数中，我分配5个单元格并将“snake_head”指向列表中的第一个元素，“snake_tail”指向最后一个元素。在第二个函数中，我尝试释放列表中的最后一个元素，并将snake_tail移动到列表中的下一个单元格。释放snake_tail时出错。我不明白它是什么。CrtIsValidHeapPointer错误，当试图释放链表的元素

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

typedef struct pos_s { 
    unsigned int x; 
    unsigned int y; 
}pos_t; 


typedef struct snake_cell_s { 
    pos_t pos; 
    struct snake_cell_s* next; 
    // struct snake_cell_s* prev; 
} snake_cell_t; 



void init_snake(snake_cell_t** snake_head, snake_cell_t** snake_tail) 
{ 
    int i; 
    const int init_snake_size = 5; 
    unsigned int init_snake_x = 5; 
    unsigned int init_snake_y = 5; 

    *snake_head = (snake_cell_t*)malloc(sizeof(snake_cell_t)*init_snake_size); 
    snake_cell_t* snake_cell[init_snake_size]; 

    for (i = 0; i<init_snake_size; ++i) { 
     snake_cell[i] = (*snake_head) + i; 
     snake_cell[i]->pos.x = init_snake_x + i; 
     snake_cell[i]->pos.y = init_snake_y; 

     if (i<init_snake_size - 1) { 
      snake_cell[i]->next = *snake_head + i + 1; 
     } 
     else { 
      snake_cell[i]->next = NULL; 
     } 
    } 
    *snake_tail = snake_cell[init_snake_size - 1]; 
    (*snake_tail)->next = NULL; 
} 




snake_cell_t* advance_snake_tail(snake_cell_t* snake_head, snake_cell_t* snake_tail) 
{ 
    snake_cell_t* snake_new_tail; 
    snake_cell_t* snake_cell = snake_head; 

    while (snake_cell->next->next != NULL) 
    { 
     snake_cell = snake_cell->next; 
    } 

    snake_new_tail = snake_cell; 
    snake_new_tail->next = NULL; 
    free(snake_tail);  // < ---- crash happens here 
    return snake_new_tail; 
} 







int main() 
{ 
    snake_cell_t* snake_head = NULL; 
    snake_cell_t* snake_tail = NULL; 
    init_snake(&snake_head, &snake_tail);  // create a 5 cell snake list 
    snake_tail = advance_snake_tail(snake_head, snake_tail); // update snake tail- remove last cell and move pointer to previous cell 
    return 0; 
}

来源

2016-06-28 sergeyrar

调试器说什么？ –

调试断言失败！计划：... 15 \项目\ ConsoleApplication1 \调试\ ConsoleApplication1.exe中文件：minkernel \ CRT显示器\ ucrt的\ src \ appcrt \堆\ debug_heap.cpp 行：888表达式：_CrtIsValidHeapPointer（块） – sergeyrar

你'free'''''''malloc'不返回的指针。 – immibis

你free荷兰国际集团不是由malloc返回一个指针。 - immibis

来源

2016-07-19 12:43:13 Armali

CrtIsValidHeapPointer错误，当试图释放链表的元素

回答

相关问题