顺序表的实现

#pragma once
#include<stdio.h>
#include<stdlib.h>
#define INIT_CAPACITY 4
typedef int SLDataType;
#define N 10
typedef struct SeqList
{
  SLDataType* a;
  int size;  //有效数据个数
  int capacity;//空间的容量
}SL;
void SLInit(SL* ps);
void SLDestory(SL* s);
void SLExpend(SL* s);
void Push_Back(SL* ps, SLDataType x);
void Pop_Back(SL* ps);
void SLPrint(SL* ps);
void Push_Front(SL* ps, SLDataType x);
void Pop_Front(SL* ps);

#include"SeqList.h"
void SeqInit(SL* ps)
{
  ps->a= (SLDataType*)malloc(sizeof(SLDataType) * INIT_CAPACITY);
  if (ps->a == NULL)
  {
    perror("malloc fail");
  }
  ps->size = 0;
  ps->capacity= INIT_CAPACITY;
}
void SLDestroy(SL* ps)
{
  free(ps->a);
  ps->a = NULL;
  ps->capacity = 0;
  ps->size = 0;
}
void SLExpend(SL* s)
{
  SLDataType* tmp = (SLDataType*)realloc(s->a, sizeof(SLDataType)*s->capacity * 2);
  if (tmp == NULL)
  {
    perror("realloc fail");
    return;
  }
  s->a = tmp;
  s->capacity *= 2;
  printf("扩容成功\n");
}
void Push_Back(SL* ps, SLDataType x)
{
  if (ps->capacity == ps->size)
  {
    SLExpend(ps);
  }
  ps->a[ps->size++] = x;
}
void SLPrint(SL* ps)
{
  for (int i = 0; i < ps->size; i++)
  {
    printf("%d ", ps->a[i]);
  }
  puts("");
}
void Pop_Back(SL* ps)
{
  if (ps->size == 0)
  {
    return;
  }
  ps->size--;
}
void Push_Front(SL* ps, SLDataType x)
{
  if (ps->capacity == ps->size)
  {
    SLExpend(ps);
  }
  int end = ps->size;
  while (end)
  {
    ps->a[end] = ps->a[end - 1];
    end--;
  }
  ps->a[0] = x;
  ps->size++;
}
void Pop_Front(SL* ps)
{
  int pos = 1;
  while (pos < ps->size)
  {
    ps->a[pos - 1] = ps->a[pos];
    pos++;
  }
  ps->size--;
}

#include"SeqList.h"
int main(void)
{
  SL s;
  SeqInit(&s);
  Push_Back(&s, 1);
  Push_Back(&s, 2);
  Push_Back(&s, 8);
  Push_Back(&s, 8);
  Push_Front(&s, 100);
  Push_Front(&s, 99);
  Push_Front(&s, 98);
  SLPrint(&s);
  Pop_Front(&s);
  Pop_Front(&s);
  SLPrint(&s);
  printf("%d %d", s.capacity, s.size);
  return 0;
}