malloc时触发断点

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

typedef struct qnode
{
    int data;            /*队列结点*/
    qnode *next;
}LQNode;

typedef struct                                                                          
{
    LQNode *front;           /*队列头尾指针*/                     
    LQNode *rear;                                 
}LQueue;

void QueueInitiate(LQueue *Q)
{
    Q->rear = NULL;
    Q->front = NULL;
}

void QueueAppend(LQueue *Q, int x)
{
    LQNode *p = (LQNode *)malloc(sizeof(LQNode));++++++++++

   p->data = x;
   p->next = NULL;

   if(Q->rear != NULL)
       Q->rear->next = p;
   Q->rear = p;
   if(Q->rear == NULL)
       Q->front == p;
}

int QueueNotEmpty(LQueue Q)
{
    if(Q. front == NULL) return 0;
    else return 1;
}

int QueueDelete(LQueue *Q,int *d)
{
    LQNode *p;

    if(Q->front == NULL){
         printf ("队列已空无数据元素出队列！ \n");
         return 0;
    }
    else{
      *d  = Q->front->data;
      p = Q->front;
      Q->front = Q->front->next;
      if(Q->front == NULL) Q->rear = NULL;
    }

      free(p);
      return 1;
}

void RadixSort(int *a,int n, int m,int d)  
{
      int i, j, k, power = 1;
      LQueue *tub;
      tub = (LQueue *)malloc(sizeof (LQueue )* d);

      for(i = 0; i < d; i++)
          QueueInitiate(&tub[i]);                           
      for(i = 0; i < m; i++){
          if(i == 0)
              power = 1;
          else
                power = power *d;
          for(j = 0; j < n; j++){
              k = a[j] /power - (a[j] /(power * d)) * d;
              QueueAppend(&tub[k], a[j]);   
          }
         
          k = 0;
          for(j = 0; j < d; j++)
              while(QueueNotEmpty(tub[j]) != 0){
                  QueueDelete(&tub[j], &a[k]);
                  k++;
              }
      }
}

void main()
{
    stu *class1 = (stu *)calloc(sizeof(stu),1);
    /*int *class1_average = (int *)malloc(sizeof(stu));*/++++++++++++++++++++
    int class1_average[8] = {21,31,41,81,51,61,71,11};

    RadixSort(class1_average,8,2,10);
    printf("OK");
   
}