strcpy() changes return array

[Fransje]

Hi all,
I don't understand line 29:

template <typename T, int nSize> // nSize is the expression parameter 
class Buffer { 
private:     // The expression parameter controls the size of the array     
    T m_atBuffer[nSize];   
public:     
    T* GetBuffer() { return m_atBuffer; }       
    T& operator[](int nIndex) {         
        return m_atBuffer[nIndex];
    } 
};   

int main() {     
    // declare an integer buffer with room for 12 chars     
    Buffer<int, 12> cIntBuffer;
       
    // Fill it up in order, then print it backwards     
    for (int nCount=0; nCount < 12; nCount++)         
        cIntBuffer[nCount] = nCount;       

    for (int nCount=11; nCount >= 0; nCount--)         
        std::cout << cIntBuffer[nCount] << " ";
     
    std::cout << std::endl;
       
    // declare a char buffer with room for 31 chars     
    Buffer<char, 31> cCharBuffer;       

    // strcpy a string into the buffer and print it     
    strcpy(cCharBuffer.GetBuffer(), "Hello there!");     
    std::cout << cCharBuffer.GetBuffer() << std::endl;       

    return 0; 
}

The return value of GetBuffer() is modified, and this return value is the buffer itself. Is it really possible to change variables in this way?

[Moschops]

The return value of GetBuffer() is modified, and this return value is the buffer itself.

The return value is a pointer to an array.

Is it really possible to change variables in this way?

Yes. If you have a pointer to a variable, you can use that pointer to read and set the variable's value (unless it is a const, of course).

[Peter87]

The return value of GetBuffer() is modified

No it isn't.

and this return value is the buffer itself

The return value of GetBuffer() is a pointer to the first element in the array m_atBuffer.

Is it really possible to change variables in this way?

strcpy receives a pointer and it is possible to change the data that a pointer points to. If you don't want to allow the data to be modified you should change GetBuffer() to return a const T*.

[Fransje]

I see. And now I understand SDL_PollEvent( &event ) as well. Thanks!