The related operations of the sequence table: Head insertion, tail insertion, head deletion, tail deletion, insertion and deletion at any position
Definition of sequence table
Define a structure to store the sequence table. The structure has three elements: the array pointer data, the number of effective elements size, and the current capacity of the array.
It should be noted here that in order to improve the applicability of the code, we have used the typedef for the data type of the array to have an alias, slDatatype, to facilitate the use of other data types in the later operation.
Initialization sequence table
Initialize the sequence table, that is, the sequence table already exists, but the content is empty
Check capacity and expansion
Since the sequence table needs to dynamically open up space for storage, it is necessary to check whether the size of the space meets the needs of inserting data during the insert operation. No matter where the element is inserted, it needs to be checked.
End insert and delete operation
End insertion: First judge whether the sequence table is legal, then check the capacity and expansion, put the data that needs to be inserted after the last valid position of the array, and then store size++, which is the data to be inserted, into the effective bits of the sequence table.
Tail deletion: Judging that the sequence table is legal, and then directly size- -, that is, the last bit is not valid data in the sequence table. This is a false deletion. The data at this location is not actually deleted, but the connection with the sequence table is cut off and cannot be used anymore.
Head plug deletion operation
Head insertion and head deletion are relatively more complicated than tail insertion and tail deletion, because they both involve the movement of elements.
Head insertion: Judging legally, check the capacity, and then move all the elements of the sequence table backward by one position in the order from back to forward, and then insert the specified element in the first position.
Header deletion: Combine head insertion and tail deletion operations, and move the elements forward by one position in the order from front to back.
Insert and delete at any position
The analogy of head plug deletion and tail insertion and tail deletion operations can be realized only at the position pos where the reentry needs to be operated. After this function is realized, the head deletion, head insertion and tail deletion and tail insertion operations can be further optimized, as long as you want pos to be set to 0 respectively. And size.
#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
typedef int slDatatype;//顺序表内的数据类型（便于维护）
//动态顺序表
typedef struct seqList
{
slDatatype *data; //数组指针
int size; //有效元素个数
int capacity; //数组内存空间
} seqList;
//初始化顺序表
void Init(seqList* sl)//形参为结构体指针
{
sl->data = NULL;
sl->size = 0;
sl->capacity = 0;
}
//检查容量及扩容
void Checkcapacity(seqList*sl)
{
if (sl->size == sl->capacity)
{
//开辟新空间
int newCapacity = sl->capacity == 0 ? 1 : 2 * sizeof(sl->capacity);
slDatatype * tmp = (slDatatype*)malloc(newCapacity*sizeof(slDatatype));
//拷贝数据
memcpy(tmp, sl->data, sizeof(slDatatype)*sl->size);
//释放原有空间
free(sl->data);
sl->data = tmp;
//若使用realloc动态开辟空间————可替换35-42行
//sl->data = (seqList*)ralloc(sl->data, newCapacity * sizeof(slDatatype));
//更新容量
sl->capacity = newCapacity;
}
}
//打印顺序表
void Listprint(seqList*sl)
{
if (sl == NULL)
return;
for (int i = 0; i < sl->size; i++)
{
printf("%d ", sl->data[i]);
}
printf("\n");
}
//尾插
void Pushback(seqList* sl,slDatatype val)
{
if (sl == NULL)
return;
Checkcapacity(sl);
sl->data[sl->size] = val;
sl->size++;
}
//尾删
void Popback(seqList* sl)
{
if (sl == NULL||sl->size==0)
return;
if (sl->size > 0)
sl->size--;
}
//头插
void Pushfront(seqList*sl,slDatatype val)
{
if (sl == NULL)
return;
//检查容量
Checkcapacity(sl);
//移动元素--从后向前
int end = sl->size;
while (end > 0)
{
sl->data[end] = sl->data[end - 1];
--end;
}
//插入元素
sl->data[0] = val;
sl->size++;
}
//头删
void Popfront(seqList* sl)
{
if (sl == NULL||sl->size==0)
return;
//从前向后移动元素
for (int i = 0; i < sl->size; i++)
{
sl->data[i] = sl->data[i + 1];
}
//更新size
sl->size--;
}
//任意位置插入元素
void Insert(seqList*sl, int pos, slDatatype val)
{
if (sl == NULL)
return;
Checkcapacity(sl);
if (pos >= 0 && pos <= sl->size)
{
//移动数据
int end = sl->size;
while (end > pos)
{
sl->data[end] = sl->data[end - 1];
end--;
}
//插入数据
sl->data[pos] = val;
sl->size++;
}
}
//删除任意位置数据
void Erase(seqList*sl, int pos)
{
if (sl == NULL || sl->size == 0)
return;
if (pos >= 0 && pos < sl->size)
{
while (pos<sl->size)
{
sl->data[pos] = sl->data[pos+1];
pos++;
}
sl->size--;
}
}
//测试模块---该部分功能根据用户需要自定义
void test()
{
seqList sl;
Init(&sl);
Pushback(&sl, 1);
Pushback(&sl, 2);
Pushback(&sl, 3);
Pushback(&sl, 4);
Erase(&sl, 1);
Listprint(&sl);
}
//销毁顺序表
void Destroy(seqList* sl)
{
if (sl != NULL && sl->data != NULL)
{
free(sl->data);
sl->data = NULL;
}
}
int main()
{
test();
return 0;
}