"0x004010e9"指令引用的"0x00000078"内存。该内存不能为"read"。

我在编快速排序的算法，但是出现了这个状况。一下是我的代码：
#include<stdio.h>
#include<stdlib.h>
#include<time.h>

typedef int KeyType;
typedef int DataType;

struct RecordNode{
    KeyType key;
    DataType info;
};

struct SortObject{
    int n;                /* n为文件中记录个数 */
    RecordNode * record;
};

void quicksort(SortObject *p,int l,int x);            /* 快排函数 */


void quicksort(SortObject *pvector, int left, int r)
{
    int i,j;
    RecordNode temp;
    if(left>=r) return;
    i=left; j=r;
    temp = pvector->record[i];
    while(i!=j){
        while( (j>i)&&(pvector->record[j].key >= temp.key) )
            j--;
        if(j>i)
            pvector->record[i++] = pvector->record[j];
        while( (j>i)&&(pvector->record[i].key <= temp.key) )
            i++;
        if(i<j)
            pvector->record[j--] = pvector->record[i];
    }
    pvector->record[i] = temp;
    quicksort(pvector, left, i-1);
    quicksort(pvector, i+1, r);
}


void main()
{
    srand(time(0));   
    int len,k;
    printf("Please input the length of record:\n");
    scanf("%d",&len);

//为记录数组申请结点空间
    SortObject * p1 = (SortObject*)malloc(sizeof(SortObject));
    if(p1 != NULL){                            //申请成功
        p1->record = (RecordNode *)malloc(sizeof(int)*len);
        if(p1->record){
            p1->n = len;
        }
        else free(p1);
    }
    else printf("Out of space!!\n");

    int num=len;
    while(num--)
        p1->record[num].key = rand()%1000;
    printf("The new record is:\n%d",p1->record[0].key);
    for( k=1; k<len; k++)
        printf("--%d",p1->record[k].key);

    quicksort(p1,0,p1->n-1);

    printf("\n\nThe sorted record is:\n%d",p1->record[0].key);
    for( k=1; k<len; k++)
        printf("--%d",p1->record[k].key);
}