顺序表插入删除，编译器没有检查出错误，但是结果没有输出。

问题遇到的现象和发生背景

编译器没有检查出错误，但是没有结果输出

问题相关代码，请勿粘贴截图

//尾插尾删，头插头删，中间插入删除，查找
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
typedef  int SLDataType;
typedef struct SqList
{
    SLDataType* a;//存储数据
    int size;//有效数据长度
    int Capacity;//开辟内存的空间    
}SL,SqList;
void SqListInit(SL* ps)//初始化
{
    ps->a=(SLDataType*)malloc(sizeof(SLDataType)*4);
    if(ps->a==NULL)
    {
        printf("初始化失败！\n");
        exit(-1);
    }
    ps->a=NULL;
    ps->size=0;
    ps->Capacity=4;
} 
void SqListCheckcapcity(SL* ps)
{
        assert(ps);
    if(ps->size>ps->Capacity)
    {
        ps->Capacity *=2;
        ps->a=(SLDataType*)realloc(ps->a,sizeof(SLDataType)*ps->Capacity);
        if(ps->a=NULL)
        {
            printf("扩容失败！\n");
            exit(-1);
        }
    }
}
void SqListprintf(SL* ps)//遍历 
{
    assert(ps);
    int i=0;
    for(;i<ps->size;i++)
    {
        printf("%d",ps->a[i]);
    }
    printf("\n");
}
void SqListpushback(SL* ps,SLDataType x)//尾插 
{
    assert(ps);
    SqListCheckcapcity(ps);
    if(ps->Capacity>0)
    {
        ps->a[ps->size]=x;
    }
    ps->size++;
}
void SqListpopback(SL* ps)
{
    assert(ps);
    ps->size--;
}
void SqListpushfront(SL* ps,SLDataType x) //头插 
{
    assert(ps);
    SqListCheckcapcity(ps);
    int end=ps->size;
    while(end>0)
    {
        ps->a[end]=ps->a[end-1];
        end--;
    }
    ps->a[0]=x;
    ps->size++;    
}
void SqListpopfront(SL* ps)
{
    assert(ps);
    int begin=0;
    while(begin<ps->size-1)
    {
        ps->a[begin]=ps->a[begin+1];
        begin++;
    }
    ps->size--;
}
void SqListinsert(SL* ps,SLDataType pos,int x)//中间插入 
{
    assert(ps);
    SqListCheckcapcity(ps);
    int end=ps->size;
    while(ps->Capacity>0&&pos<end)
    {
        ps->a[end]=ps->a[end-1];
        end--;
    }
    ps->a[pos]=x;
    ps->size++;
}
void SqListerase(SL* ps,SLDataType pos)
{
    assert(ps);
    int end=ps->size-1;
    if(ps->Capacity>0&&pos<end)
    {
        ps->a[pos]=ps->a[pos+1];
        pos++;
    }
    ps->size--;
}
int main(void)
{
    SqList ps;
    SqListInit(&ps);
    SqListpushback(&ps,1);//尾插
    SqListpushback(&ps,2);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps,3);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps,4);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps,5);//尾插
    SqListprintf(&ps);//遍历 
    SqListpopback(&ps);//尾删 
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps,9);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps,8);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps,7);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps,6);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpopfront(&ps);//头删，向前边移，前边的先移
    SqListprintf(&ps);//遍历  
    return 0;
} 

运行结果及报错内容

我想要达到的结果

希望找到问题所在！谢谢

修改的部分在代码中有注释，代码修改如下：

//尾插尾删，头插头删，中间插入删除，查找
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
typedef  int SLDataType;
typedef struct SqList
{
    SLDataType* a;//存储数据
    int size;//有效数据长度
    int Capacity;//开辟内存的空间    
}SL, SqList;
void SqListInit(SL* ps)//初始化
{
    ps->a = (SLDataType*)malloc(sizeof(SLDataType) * 4);
    if (ps->a == NULL)
    {
        printf("初始化失败！\n");
        exit(-1);
    }
    //ps->a = NULL;  //修改1  已经申请空间了，这里不应该再设置为NULL
    ps->size = 0;
    ps->Capacity = 4;
}
void SqListCheckcapcity(SL* ps)
{
    assert(ps);
    if (ps->size >= ps->Capacity) //修改2，这里应该是>=
    {
        ps->Capacity *= 2;
        ps->a = (SLDataType*)realloc(ps->a, sizeof(SLDataType) * ps->Capacity);
        if (ps->a == NULL) //修改3 应该是 ==，不是=
        {
            printf("扩容失败！\n");
            exit(-1);
        }
    }
}
void SqListprintf(SL* ps)//遍历 
{
    assert(ps);
    int i = 0;
    for (; i < ps->size; i++)
    {
        printf("%d", ps->a[i]);
    }
    printf("\n");
}
void SqListpushback(SL* ps, SLDataType x)//尾插 
{
    assert(ps);
    SqListCheckcapcity(ps);
    if (ps->Capacity > ps->size ) //修改4 ps->Capacity > 0
    {
        ps->a[ps->size] = x;
    }
    ps->size++;
}
void SqListpopback(SL* ps)
{
    assert(ps);
    ps->size--;
}
void SqListpushfront(SL* ps, SLDataType x) //头插 
{
    assert(ps);
    SqListCheckcapcity(ps);
    int end = ps->size;
    while (end > 0)
    {
        ps->a[end] = ps->a[end - 1];
        end--;
    }
    ps->a[0] = x;
    ps->size++;
}
void SqListpopfront(SL* ps)
{
    assert(ps);
    int begin = 0;
    while (begin < ps->size - 1)
    {
        ps->a[begin] = ps->a[begin + 1];
        begin++;
    }
    ps->size--;
}
void SqListinsert(SL* ps, SLDataType pos, int x)//中间插入 
{
    assert(ps);
    SqListCheckcapcity(ps);
    int end = ps->size;
    while (ps->Capacity > 0 && pos < end)
    {
        ps->a[end] = ps->a[end - 1];
        end--;
    }
    ps->a[pos] = x;
    ps->size++;
}
void SqListerase(SL* ps, SLDataType pos)
{
    assert(ps);
    int end = ps->size - 1;
    if (ps->Capacity > 0 && pos < end)
    {
        ps->a[pos] = ps->a[pos + 1];
        pos++;
    }
    ps->size--;
}
int main(void)
{
    SqList ps;
    SqListInit(&ps);
    SqListpushback(&ps, 1);//尾插
    SqListpushback(&ps, 2);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps, 3);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps, 4);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps, 5);//尾插
    SqListprintf(&ps);//遍历 
    SqListpopback(&ps);//尾删 
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps, 9);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps, 8);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps, 7);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps, 6);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpopfront(&ps);//头删，向前边移，前边的先移
    SqListprintf(&ps);//遍历  
    return 0;
}

根据返回信息看，应该是指针操作错误崩溃了
第20行应该删除啊，前面给a分配了空间，怎么突然加一行将a设置为空呢？设置为空后面还怎么玩
第31行错了， if(ps->a=NULL) 改为 if(ps->a==NULL)
第28行分配空间在等于时就需要分配

//尾插尾删，头插头删，中间插入删除，查找
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
typedef  int SLDataType;
typedef struct SqList
{
    SLDataType* a;//存储数据
    int size;//有效数据长度
    int Capacity;//开辟内存的空间    
}SL,SqList;
void SqListInit(SL* ps)//初始化
{
    ps->a=(SLDataType*)malloc(sizeof(SLDataType)*4);
    if(ps->a==NULL)
    {
        printf("初始化失败！\n");
        exit(-1);
    }
 //   ps->a=NULL;
    ps->size=0;
    ps->Capacity=4;
} 
void SqListCheckcapcity(SL* ps)
{
        assert(ps);
    if(ps->size>=ps->Capacity)
    {
        ps->Capacity *=2;
        ps->a=(SLDataType*)realloc(ps->a,sizeof(SLDataType)*ps->Capacity);
        if(ps->a==NULL)
        {
            printf("扩容失败！\n");
            exit(-1);
        }
    }
}
void SqListprintf(SL* ps)//遍历 
{
    assert(ps);
    int i=0;
    for(;i<ps->size;i++)
    {
        printf("%d",ps->a[i]);
    }
    printf("\n");
}
void SqListpushback(SL* ps,SLDataType x)//尾插 
{
    assert(ps);
    SqListCheckcapcity(ps);
    if(ps->Capacity>0)
    {
        ps->a[ps->size]=x;
    }
    ps->size++;
}
void SqListpopback(SL* ps)
{
    assert(ps);
    ps->size--;
}
void SqListpushfront(SL* ps,SLDataType x) //头插 
{
    assert(ps);
    SqListCheckcapcity(ps);
    int end=ps->size;
    while(end>0)
    {
        ps->a[end]=ps->a[end-1];
        end--;
    }
    ps->a[0]=x;
    ps->size++;    
}
void SqListpopfront(SL* ps)
{
    assert(ps);
    int begin=0;
    while(begin<ps->size-1)
    {
        ps->a[begin]=ps->a[begin+1];
        begin++;
    }
    ps->size--;
}
void SqListinsert(SL* ps,SLDataType pos,int x)//中间插入 
{
    assert(ps);
    SqListCheckcapcity(ps);
    int end=ps->size;
    while(ps->Capacity>0&&pos<end)
    {
        ps->a[end]=ps->a[end-1];
        end--;
    }
    ps->a[pos]=x;
    ps->size++;
}
void SqListerase(SL* ps,SLDataType pos)
{
    assert(ps);
    int end=ps->size-1;
    if(ps->Capacity>0&&pos<end)
    {
        ps->a[pos]=ps->a[pos+1];
        pos++;
    }
    ps->size--;
}
int main(void)
{
    SqList ps;
    SqListInit(&ps);
    SqListpushback(&ps,1);//尾插
    SqListpushback(&ps,2);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps,3);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps,4);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps,5);//尾插
    SqListprintf(&ps);//遍历 
    SqListpopback(&ps);//尾删 
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps,9);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps,8);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps,7);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps,6);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpopfront(&ps);//头删，向前边移，前边的先移
    SqListprintf(&ps);//遍历 
    system("pause");
    return 0;
} 

```c
//尾插尾删，头插头删，中间插入删除，查找
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
typedef  int SLDataType;
typedef struct SqList
{
    SLDataType* a;//存储数据
    int size;//有效数据长度
    int Capacity;//开辟内存的空间    
}SL, SqList;
void SqListInit(SL* ps)//初始化
{
    ps->a = (SLDataType*)malloc(sizeof(SLDataType) * 4);
    if (ps->a == NULL)
    {
        printf("初始化失败！\n");
        exit(-1);
    }
    //【主要错误】这里将刚分配的内存丢失了
    //ps->a = NULL;
    ps->size = 0;
    ps->Capacity = 4;
}
void SqListCheckcapcity(SL* ps)
{
    assert(ps);
    //if (ps->size > ps->Capacity)
    if (ps->size >= ps->Capacity)
    {
        ps->Capacity *= 2;
        ps->a = (SLDataType*)realloc(ps->a, sizeof(SLDataType)*ps->Capacity);
        if (ps->a == NULL)
        {
            printf("扩容失败！\n");
            exit(-1);
        }
    }
}
void SqListprintf(SL* ps)//遍历 
{
    assert(ps);
    int i = 0;
    for (; i < ps->size; i++)
    {
        printf("%d", ps->a[i]);
    }
    printf("\n");
}
void SqListpushback(SL* ps, SLDataType x)//尾插 
{
    assert(ps);
    SqListCheckcapcity(ps);
    
    if (ps->Capacity > 0)
    ps->a[ps->size] = x;
    ps->size++;
}
void SqListpopback(SL* ps)
{
    assert(ps);
    ps->size--;
}
void SqListpushfront(SL* ps, SLDataType x) //头插 
{
    assert(ps);
    SqListCheckcapcity(ps);
    int end = ps->size;
    while (end > 0)
    {
        ps->a[end] = ps->a[end - 1];
        end--;
    }
    ps->a[0] = x;
    ps->size++;
}
void SqListpopfront(SL* ps)
{
    assert(ps);
    int begin = 0;
    //while (begin < ps->size - 1)
    //需要-2 因为从0开始最大应该到size-1 但是下面会执行到begin+1 所以实际到了size 会越界
    while (begin < ps->size - 2) 
    {
        ps->a[begin] = ps->a[begin + 1];
        begin++;
    }
    ps->size--;
}
void SqListinsert(SL* ps, SLDataType pos, int x)//中间插入 
{
    assert(ps);
    SqListCheckcapcity(ps);
    int end = ps->size;
    while (ps->Capacity > 0 && pos < end)
    {
        ps->a[end] = ps->a[end - 1];
        end--;
    }
    ps->a[pos] = x;
    ps->size++;
}
void SqListerase(SL* ps, SLDataType pos)
{
    assert(ps);
    int end = ps->size - 1;
    if (ps->Capacity>0 && pos < end)
    {
        ps->a[pos] = ps->a[pos + 1];
        pos++;
    }
    ps->size--;
}
int main(void)
{
    SqList ps;
    SqListInit(&ps);
    SqListpushback(&ps, 1);//尾插
    SqListpushback(&ps, 2);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps, 3);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps, 4);//尾插
    SqListprintf(&ps);//遍历 
    SqListpushback(&ps, 5);//尾插
    SqListprintf(&ps);//遍历 
    SqListpopback(&ps);//尾删 
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps, 9);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps, 8);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps, 7);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpushfront(&ps, 6);//头插，向后边挪，后边的先移
    SqListprintf(&ps);//遍历 
    SqListpopfront(&ps);//头删，向前边移，前边的先移
    SqListprintf(&ps);//遍历  
    getchar();
    return 0;
}

```

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