顺序表各项功能的接口及实现

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<assert.h>
typedef int SLDatatype;
typedef struct SeqList
{
	SLDatatype* a;   //存储数据空间的指针
	int size;  //有效数据的个数
	int capacity; //容量空间大小
}SeqList;

//接口
void SeqListInit(SeqList* ps);//初始化
void SeqListDestory(SeqList* ps);//销毁
void SeqListPrint(SeqList* ps);//打印
void SeqListPushBack(SeqList* ps, SLDateType x);//尾插
void SeqListPushFront(SeqList* ps, SLDateType x);//头插
void SeqListPopFront(SeqList* ps);//头删
void SeqListPopBack(SeqList* ps);//尾删
int SeqListFind(SeqList* ps, SLDateType x);// 顺序表查找
void SeqListInsert(SeqList* ps, size_t pos, SLDateType x);// 顺序表在pos位置插入x
void SeqListErase(SeqList* ps, size_t pos);// 顺序表删除pos位置的值

//接口实现
//初始化
void SeqListInit(SeqList* ps)
{
	ps->a = (SLDataType*)malloc(sizeof(SLDataType)* 4);
	if (ps->a == NULL)//判断是否增容成功
	{
		printf("malloc fail \n")
		exit(-1);
	}
	memset(ps->a, 0, sizeof(SLDatatype)* 4);//把数组的每个字节都初始化为0（可有可无）
    ps->size = 0;//有效个数为0
    ps->capacity = 4;//空间为4
}
//销毁
void SeqListDestory(SeqList* ps)
{
	free(ps->a);
	ps->a = NULL;//把a置为空
	ps->size = ps->capacity = 0;//有效个数和空间都置为0
}
//打印
void SeqListPrint(SeqList* ps)
{
	for (int i = 0; i < ps ->size; i++)
	{
		printf("%d ", ps->a[i]);
	}
	printf("\n");
}
//增容
void CheckCapacity(SeqList* ps)
{
	if (ps->size == ps->capacity)//空间不够，需要增容，一般情况变为原来的二倍
	{
		SLDatatype* tmp = (SLDatatype*)realloc(ps->a, sizeof(SLDatatype)*ps->capacity * 2);
		if (tmp == NULL)//判断是否增容成功
		{
			printf("realloc fail \n")
			exit(-1);
		}
	}
	ps->a = tmp;//把有新的空间给a
	ps->capacity *= 2;空间变为原来的二倍
}
//尾插
void SeqListPushBack(SeqList* ps, SLDateType x)
{
	assert(ps);
	CheckCapacity(ps);//调用上面的增容接口
	ps->a(ps->size) = x;//直接在尾部插入x
	ps ->size++;
}
//头插
void SeqListPushFront(SeqList* ps, SLDateType x)
{
	assert(ps);
	CheckCapacity(ps);
	int end = ps->size - 1;
	while (end <= 0)
	{
		ps->a[end + 1] == ps->a[end];
		end--;
	}
	ps->a[0] = x;
	ps->size++;
}

//尾删
void SeqListPopBack(SeqList* ps)
{
	assert(ps);
	//若无此步骤size为0时再size--为-1
	assert(ps->size > 0);
	ps->size--;
}
//头删
void SeqListPopFront(SeqList* ps)
{
	int begin = 1;
	while (begin < ps->size)
	{
		ps->a[begin - 1] = ps->a[begin];
		begin++;
	}
	ps->size--;
}
// 顺序表查找
int SeqListFind(SeqList* ps, SLDateType x)
{
	//顺序表查找,可以查找一个数在不在数组里，并返回其下标，配合其他接口使用
		assert(ps);
		for (int i = 0; i < ps->size; ++i)
		{
			if (ps->a[i] == x)
			{
				return i;
			}
		}
		return -1;
	}

// 顺序表在pos位置插入x
void SeqListInsert(SeqList* ps, size_t pos, SLDateType x)
{
	assert(ps);
	assert(pos >= 0 && pos < ps->size);
	CheckCapacity(ps);
	int end = ps->size - 1;
	while (end >= pos)
	{
		ps->a[end + 1] = ps->a[end];
		end--;
	}
	ps->a[pos] = x;
	ps->size++;
}
// 顺序表删除pos位置的值
void SeqListErase(SeqList* ps, size_t pos)
{
	assert(ps);
	assert(pos >= 0 && pos < ps->size);
	int begin = 0;
	while (pos < ps->size - 1)
	{
		ps->a[pos] = ps->a[pos + 1];
		pos++;
	}
	ps->size--;
}