才开始学,遇到如下问题,请指教一下:
这里为什么初始化时,不先定义一个SqList *p;运行就出错呢?


void InitList(SqList *L) // 这个能通过.
{
SqList *p;
p = (SqList *)malloc(List_Maxsize * sizeof(SqList));
if(!p) exit (OVERFLOW);
p=L;
L->length=0;
printf("InitList is OK!\n\t The L.length = %d",L->length);
}

int Input_SqL(SqList *L)
{
int i=0;
InitList(L);
printf("\nPlease Input:\n");
while((scanf("%d",&L->data[i++]))==1&&i<ListMax) ++L->length;
printf("\n\n\tInput_SqL: L->length = %d\n",L->length);
}

/*
void InitList(SqList *L) // 这个为什么不行?
{
L = (SqList *)malloc(List_Maxsize * sizeof(SqList));
if(!L) exit (OVERFLOW);
L->length=0;
printf("InitList is OK!\n\t The L.length = %d",L->length);
}
*/

[QUOTE](SqList *L)

L = (SqList *)malloc(List_Maxsize * sizeof(SqList));[/QUOTE]

形参属于编译器自动分配内存.
你的L已经被编译器自动分配过了
之后你又想动态的再一次分配.这个当然不可以.
两种分配方法并不是在同一个存储区中!

(SqList *L)

L = (SqList *)malloc(List_Maxsize * sizeof(SqList));