Question

Suppose I have below program,

 typedef struct xyz
    {
    int abc[6];//int abc;
    //int yz;
    }xyz;
    int main()
    {
    int *ptr = new int(10);
    int *ptr1 = new int(20);

    xyz* XYZ = reinterpret_cast <xyz*>(ptr); //Initializes XYZ->abc[0]
    XYZ = reinterpret_cast <xyz*>(ptr1);//Initializes XYZ->abc[0]

    }

Here the value enters into zeroth location. If I would like to push the value into XYZ->abc[1], then how can I do this?

Answer 1

Maybe you want to do

 XYZ = reinterpret_cast<xyz*> (ptr1+1);

But this kind of code is disgusting, it probably is an undefined behavior (because ptr1+1 might not be a valid location, and you could get a segmentation fault), so you should avoid doing that.

I actually don’t understand the motivation (and use case) of your question.

Maybe you wanted to allocate ten ints on the heap. Then code

int *ptr = new int[10];

and don’t forget to initialize them, e.g. with memset (ptr, 0, sizeof(int)*10);

On Linux systems, I strongly suggest to compile with g++ -Wall -g and to use valgrind and gdb to debug your program. You really want to know these tools.