Question

I am trying to store two integer value into an char array in C++.
Here is the code..

char data[20];
*data = static_cast <char> (time_delay);   //time_delay is of int type
*(data + sizeof(int)) = static_cast<char> (wakeup_code);  //wakeup_code is of int type

Now on the other end of the program, I want to reverse this operation. That is, from this char array, I need to obtain the values of time_delay and wakeup_code.

How can I do that??

Thanks,
Nick

P.S: I know this is a stupid way to do this, but trust me its a constraint.

Answer 1

I think when you write static_cast<char>, that value is converted to a 1-byte char, so if it didn’t fit in a char to begin with, you’ll lose data.

What I’d do is use *((int*)(data+sizeof(int))) and *((int*)(data+sizeof(int))) for both reading and writing ints to the array.

*((int*)(data+sizeof(int))) = wakeup_code;
....
wakeup_code = *((int*)(data+sizeof(int)));

Alternatively, you might also write:

reinterpret_cast<int*>(data)[0]=time_delay;
reinterpret_cast<int*>(data)[1]=wakeup_code;