C - 无法使用指针执行函数

Question

嘿伙计们，这是我第一次使用堆栈溢出:D我收到此错误:

Unhandled exception at 0x0105F338 (ucrtbased.dll) in Assignment_5.exe: 0xC0000005: Access violation reading location 0xCDCDCDCD.

Exception thrown at 0x0105F338 (ucrtbased.dll) in Assignment_5.exe: 0xC0000005: Access violation reading location 0xCDCDCDCD.

这是主要的:

void Test2(char* arr[], int size_arr, char* str, int size_res, char* str_cmp)
{
    int size_res_new;
    char** tempStringArr = LowerSTR(arr, size_arr, str, &size_res_new);

    if (tempStringArr == NULL)
    {
        printf("Can't allocate arr (-4)\n");
        return;
    }

    if (size_res_new != size_res)
    {
        printf("The amount of string is not correct (-4)\n");
        return;
    }

    for (int i = 0; i < size_res; i++)
    {
        if (strcmp(tempStringArr[i], str_cmp) == 0)
        {
            return;
        }
    }
    printf("No String: %s (-4)\n", str_cmp);
}

这是函数:

char** LowerSTR(char* arr[], int size_arr, char* str, int* size_res)
{
    char** newArr = NULL, counter=0;
    newArr = (char**)malloc(size_arr * sizeof(char*));
    if(newArr == NULL)
    {
        printf("Memory not allocated.\n");
        exit(0);
    }

    for(int i=0; i<size_arr; i++)
    {
        if (strcmp(arr[i], str) < 0) {
            newArr[counter] = (char*)malloc(sizeof(char) * strlen(arr[i]));
            if (newArr[counter] == NULL)
            {
                printf("Memory not allocated.\n");
                exit(0);
            }
            strcpy(newArr[counter], arr[i]);
        }
        else
            counter++;
    }
    *size_res = size_arr - counter;
    newArr = (char**)realloc(newArr, sizeof(char*) * (*size_res));
    return newArr;
}

Answer 1

        newArr[counter] = (char*)malloc(sizeof(char) * strlen(arr[i])); // allocate strlen(arr[i]) bytes
        if (newArr[counter] == NULL)
        {
            printf("Memory not allocated.\n");
            exit(0);
        }
        strcpy(newArr[counter], arr[i]); // copy 1+strlen(arr[i]) bytes. oops.

您分配了 strlen(arr[i]) 字节，但随后尝试将 arr[i] 复制到您分配的缓冲区中。但它的一个字节太少了，因为字符串末尾有一个 null 字符。您需要再分配一个字节。像 valgrind 这样的工具应该会告诉你这一点。