Using void in functions. Won't recognise

Question

I'm having a problem with this function. The function is supposed to return a type of StoredData .

This is my struct:

struct StoredData
{
    void* data;
    int size;
    int type;
    int compareValue;

    StoredData():

        size(0),
        type(0),
        compareValue(0){}
};

And this is my function:

StoredData SDI::Array::create(int size, int type, int compareValue)
{
    StoredData temp;
    void* data;
    int input;
    int input2;
    std::cout<<"What type of data would you like to insert?"<<std::endl;
    std::cout<<"1 - Integer"<<std::endl;
    std::cout<<"2 - Boolean"<<std::endl;
    std::cin>>input;
    std::cout<<"What is the value?"<<std::endl;
    std::cin>>input2;
    switch (input)
    {
    case 1:
        size = sizeof(int);
        type = 0;
        data = new int;
        *data = (int)input2;
        break;
    case 2:
        size = sizeof(bool);
        type = 1;
        data = new bool;
        *data = (bool)input2;
        break;
    }
    temp.compareValue=input2;
    temp.data = data;
    temp.type = type;
    temp.size = size;
}

Unfortunately, I'm having a problem with the line within the case statements with

*data = (bool)input2;

The error that I'm getting is that it must be a pointer to a complete object type. I need the void variable to recognize the data, and I'm getting no luck. Anybody know a workaround?

I'm getting 2 error messages for each. The first is,

illegal indirection

And the second ones are,

error C2440: '=' : cannot convert from 'int' to 'void *'

error C2440: '=' : cannot convert from 'bool' to 'void *'

Answer 1

You can't dereference a void pointer. You will have to cast it to a pointer type you can dereference:

*(bool *) data = (bool) input2;

Answer 2

You are attempting to dereference a void pointer and set its value:

*data = (bool)input2;

This is meaningless to the compiler. What type will the result of *data be?

You need to cast the void* to something meaningful first:

*(bool*)data = (bool)input2;

Alternatively, you could initialize your dynamic variables with the correct values when you create them:

data = new int(input2);
...
data = new bool(input2);

Which wouldn't require you to cast anything.

Answer 3

void是不完整的类型。您不能创建不完整类型的对象。

Answer 4

You can't dereference a plain void* , as it could point to basically anything. You aither have to make it point to something other (assigning to another pointer):

bool* bool_pointer = new bool;
*bool_pointer = static_cast<bool>(input2);
data = bool_pointer;

Or use typecasting:

*reinterpret_cast<bool*>(data) = static_cast<bool>(input2);