具有有效索引的数组在c中未返回正确的状态代码

我这里有两个函数，对于intarr_set（），如果索引有效，我会将ia[index]处的值设置为val并返回intarr_OK，这是一个状态码，如果索引也有效，另一个函数intarr_get（）会将*I设置为ia[index]。但是当我用我生成的一个随机数组测试我的函数时，它是[11 49 36 3 69 21 72 73 94 69 2 22 2 96 64 93]，我收到一条消息说我的intarr_get（）函数没有返回intarr_OK，即使我得到了一个有效的索引。有人知道我哪里出错了吗

以下是我的数组结构：

typedef struct {
  int* data;
  unsigned int len;
} intarr_t;

以下是我的intarr\U集合函数：

intarr_result_t intarr_set( intarr_t* ia, 
                unsigned int index, 
                int val )

{
    if (ia == NULL)
    {
        return INTARR_BADARRAY;
    }
    else
    {
        if ( ia->data[index] != 0 )
        {
            ia->data[index] = val;
            return INTARR_OK;
        }
        else
        {
            return INTARR_BADINDEX;
        }
    }
    return 0;
}

这是我的intarr_get函数：

intarr_result_t intarr_get( const intarr_t* ia, 
                unsigned int index, 
                int* i )
{
    if (ia == NULL)
    {
        return INTARR_BADARRAY;
    }
    else
    {
        if (ia->data[index] != 0)
        {
            if (i != NULL)
            {
                *i = ia->data[index];
            }
            return INTARR_OK;
        }
        else
        {
            return INTARR_BADINDEX;
        }
    }
    return 0;
}

---

intarr\u set

和

intarr\u get

函数的问题在于测试无效索引的方式。正确的处理方法是将

ai->data

的当前分配大小存储为

ai->len

。保持当前分配的大小可以方便地根据

ai->len

测试

索引

，以确定有效性。它还提供了一种当前方法，即使您在以后的某个时间使用

realloc

ai->data

也可以将大小保持在当前大小。所作的修改是：

intarr_result_t intarr_set( intarr_t* ia, 
                unsigned int index, 
                int val )
{
    ...
        // if ( ia->data[index] != 0 )
        if ( index < ia->len )
}

intarr_result_t intarr_get( const intarr_t* ia, 
                unsigned int index, 
                int* i )
{
    ...
        // if (ia->data[index] != 0)
        if ( index < ia->len )
}

输出：

Setting and retrieving array values, valid index (0 < index < 16)

  set myarr.data[11] = 1  (return: INTARR_OK)
  got myarr.data[11] = 1  (return: INTARR_OK)
  set myarr.data[49] = 2  (return: INTARR_BADINDEX)
  got myarr.data[49] = 1  (return: INTARR_BADINDEX)
  set myarr.data[36] = 3  (return: INTARR_BADINDEX)
  got myarr.data[36] = 1  (return: INTARR_BADINDEX)
  set myarr.data[ 3] = 4  (return: INTARR_OK)
  got myarr.data[ 3] = 4  (return: INTARR_OK)
  set myarr.data[69] = 5  (return: INTARR_BADINDEX)
  got myarr.data[69] = 4  (return: INTARR_BADINDEX)
  set myarr.data[21] = 6  (return: INTARR_BADINDEX)
  got myarr.data[21] = 4  (return: INTARR_BADINDEX)
  set myarr.data[72] = 7  (return: INTARR_BADINDEX)
  got myarr.data[72] = 4  (return: INTARR_BADINDEX)
  set myarr.data[73] = 8  (return: INTARR_BADINDEX)
  got myarr.data[73] = 4  (return: INTARR_BADINDEX)
  set myarr.data[94] = 9  (return: INTARR_BADINDEX)
  got myarr.data[94] = 4  (return: INTARR_BADINDEX)
  set myarr.data[69] = 10  (return: INTARR_BADINDEX)
  got myarr.data[69] = 4  (return: INTARR_BADINDEX)
  set myarr.data[ 2] = 11  (return: INTARR_OK)
  got myarr.data[ 2] = 11  (return: INTARR_OK)
  set myarr.data[22] = 12  (return: INTARR_BADINDEX)
  got myarr.data[22] = 11  (return: INTARR_BADINDEX)
  set myarr.data[ 2] = 13  (return: INTARR_OK)
  got myarr.data[ 2] = 13  (return: INTARR_OK)
  set myarr.data[96] = 14  (return: INTARR_BADINDEX)
  got myarr.data[96] = 13  (return: INTARR_BADINDEX)
  set myarr.data[64] = 15  (return: INTARR_BADINDEX)
  got myarr.data[64] = 13  (return: INTARR_BADINDEX)
  set myarr.data[93] = 16  (return: INTARR_BADINDEX)
  got myarr.data[93] = 13  (return: INTARR_BADINDEX)

Resulting myarr.data array

  myarr.data[ 0] = 0
  myarr.data[ 1] = 0
  myarr.data[ 2] = 13
  myarr.data[ 3] = 4
  myarr.data[ 4] = 0
  myarr.data[ 5] = 0
  myarr.data[ 6] = 0
  myarr.data[ 7] = 0
  myarr.data[ 8] = 0
  myarr.data[ 9] = 0
  myarr.data[10] = 0
  myarr.data[11] = 1
  myarr.data[12] = 0
  myarr.data[13] = 0
  myarr.data[14] = 0
  myarr.data[15] = 0

设置和检索数组值，有效索引（0

不确定是否与您的问题直接相关，但

ia->data[index]！=0不是对错误索引的正确检查。即使索引超出范围，值也可能不等于0；即使索引在数组的范围内，值也可能等于0（根据您的代码）。@Daniel是的，我也考虑过这一点。检查ia->data[index]len是否是检查有效索引的更好方法？不需要检查数据，只需检查索引本身<代码>索引len

此行：if（ia->data[index]！=0）仅表示ia->data指针的偏移量（可能是随机的）恰好包含0。您真正想要做的是将索引与ia->len进行比较，即如果（indexlen），这是因为C没有数组边界检查。此外，这种未经检查/随机写入某个偏移量到malloc的内存区域可能会导致1）malloc阵列结构损坏2）导致seg故障事件3）导致一些随机灾难。

Setting and retrieving array values, valid index (0 < index < 16)

  set myarr.data[11] = 1  (return: INTARR_OK)
  got myarr.data[11] = 1  (return: INTARR_OK)
  set myarr.data[49] = 2  (return: INTARR_BADINDEX)
  got myarr.data[49] = 1  (return: INTARR_BADINDEX)
  set myarr.data[36] = 3  (return: INTARR_BADINDEX)
  got myarr.data[36] = 1  (return: INTARR_BADINDEX)
  set myarr.data[ 3] = 4  (return: INTARR_OK)
  got myarr.data[ 3] = 4  (return: INTARR_OK)
  set myarr.data[69] = 5  (return: INTARR_BADINDEX)
  got myarr.data[69] = 4  (return: INTARR_BADINDEX)
  set myarr.data[21] = 6  (return: INTARR_BADINDEX)
  got myarr.data[21] = 4  (return: INTARR_BADINDEX)
  set myarr.data[72] = 7  (return: INTARR_BADINDEX)
  got myarr.data[72] = 4  (return: INTARR_BADINDEX)
  set myarr.data[73] = 8  (return: INTARR_BADINDEX)
  got myarr.data[73] = 4  (return: INTARR_BADINDEX)
  set myarr.data[94] = 9  (return: INTARR_BADINDEX)
  got myarr.data[94] = 4  (return: INTARR_BADINDEX)
  set myarr.data[69] = 10  (return: INTARR_BADINDEX)
  got myarr.data[69] = 4  (return: INTARR_BADINDEX)
  set myarr.data[ 2] = 11  (return: INTARR_OK)
  got myarr.data[ 2] = 11  (return: INTARR_OK)
  set myarr.data[22] = 12  (return: INTARR_BADINDEX)
  got myarr.data[22] = 11  (return: INTARR_BADINDEX)
  set myarr.data[ 2] = 13  (return: INTARR_OK)
  got myarr.data[ 2] = 13  (return: INTARR_OK)
  set myarr.data[96] = 14  (return: INTARR_BADINDEX)
  got myarr.data[96] = 13  (return: INTARR_BADINDEX)
  set myarr.data[64] = 15  (return: INTARR_BADINDEX)
  got myarr.data[64] = 13  (return: INTARR_BADINDEX)
  set myarr.data[93] = 16  (return: INTARR_BADINDEX)
  got myarr.data[93] = 13  (return: INTARR_BADINDEX)

Resulting myarr.data array

  myarr.data[ 0] = 0
  myarr.data[ 1] = 0
  myarr.data[ 2] = 13
  myarr.data[ 3] = 4
  myarr.data[ 4] = 0
  myarr.data[ 5] = 0
  myarr.data[ 6] = 0
  myarr.data[ 7] = 0
  myarr.data[ 8] = 0
  myarr.data[ 9] = 0
  myarr.data[10] = 0
  myarr.data[11] = 1
  myarr.data[12] = 0
  myarr.data[13] = 0
  myarr.data[14] = 0
  myarr.data[15] = 0