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


#define LIST_INIT_SIZE 100
#define LISTINCREMENT 10


typedef struct
{
int *elem;
int length;
int listsize;
}SqList;


SqList InitList()
{
SqList L;
L.elem=(int *)malloc(LIST_INIT_SIZE* sizeof(int));
if(!L.elem)exit(0);
L.length=0;
L.listsize=LIST_INIT_SIZE;
return L;
}
/**********************************************************/


void ListInsert(SqList L, int i, int e)
{
int *newbase;
int *p,*q;
if(i<1||i>L.length+1)
printf("error");
if(L.length>=L.listsize)
{
newbase=(int *)realloc(L.elem,(L.listsize+LISTINCREMENT)*sizeof(int));
if(!newbase)exit(0);
L.elem=newbase;
L.listsize+=LISTINCREMENT;
}
q=&(L.elem[i-1]);
for(p=&(L.elem[L.length-1]);p>=q;--p)
*(p+1)=*p;
*q=e;
++L.length;
}
/**********************************************************/


void ListDelete(SqList L, int i)
{
int *p,*q;
if(i<1||i>L.length)
printf("error");
p=&(L.elem[i-1]);
q=L.elem+L.length-1;
for(++p;p<=q;++p)
*(p-1)=*p;
--L.length;
}


/**********************************************************/


void GetElem(SqList L, int i)
{int *p, e;
//printf("Enter the location of the lookup element:\n");
//scanf("%d",&i);
p=&(L.elem[i-1]);
e=*p;
printf("the element in this location is:");
printf("%d",e);
printf("\n");
}


/**********************************************************/
void ListInvert(SqList L)
{
int *s,i;
for(i=0;i<L.length/2;i++)
{s=L.elem[i];
L.elem[i]=L.elem[L.length-i-1];
L.elem[L.length-i-1]=s;
}
printf("The elements in the new linear are:\n");
for(i=0;i<L.length;i++)
printf("%d",L.elem[i]);
printf("\n");


}






int main(void)
{
int i,m,e;
SqList L;
L=InitList();
printf("Enter table length:");
scanf("%d",&L.length);
printf("\n");


printf("Enter elements:");
printf("\n");
for(i=0;i<L.length;i++)
scanf("%d",&L.elem[i]);
printf("The elements in the table are:");
printf("\n");
for(i=0;i<L.length;i++)
printf("%d",L.elem[i]);
printf("\n");


printf("Select:");
printf("\n");
printf("1insert element:\n");
printf("2delect element:\n");
printf("3find element\n");
printf("4inversion element\n");
scanf("%d",&m);


switch(m)
{
case 1 :
printf("Enter the position of the insert element i:\n");
scanf("%d",&i);
printf("Enter the new element to be inserted e:\n");
scanf("%d",&e);


ListInsert(L,  i,  e);
printf("The elements in the new linear are:\n");
for(i=0;i<L.length+1;i++)
printf("%d",L.elem[i]);
printf("\n");
break;
case 2 :
printf("Enter the position of the delete element:\n");
scanf("%d",&i);
ListDelete(L,  i);

printf("The elements in the new linear are:\n");
for(i=0;i<L.length-1;i++)
printf("%d",L.elem[i]);
printf("\n");
break;


case 3 :
printf("Enter the location of the element to be found:\n");
scanf("%d",&i);
GetElem( L,   i);
break;
case 4 :
ListInvert( L);
break;


default:printf("error");

}

}

問：  q=L.elem+L.length-1;  {這裡的L.elem 是地址，為什麼可以直接和表長相加？}

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