Setting multiple array values after declaration-CodePudding

Is there any way to set the values in an array after it has been declared?

unsigned char values[16];
// Some other code to decide what to put into the values array
values = {0xAA,0xBB,0xCC,0xDD};

I saw this solution but it is for a C implementation. I'm trying to be efficient on memory and avoid a memcpy as well as I don't always need to fill the entire array like in the example above. So far this is the only method that I know works but its very kludgy.

unsigned char values[16];
// Some other code to decide what to put into the values array
values[0] = 0xAA;
values[1] = 0xBB;
values[2] = 0xCC;
values[3] = 0xDD;

CodePudding user response：

Maybe something like this would do:

unsigned char* values;
// Some other code to decide what to put into the values array
values = (unsigned char[]) {0xAA,0xBB,0xCC,0xDD};

Appendix: Note that it really depends on what you need. Since values is not an array anymore in this case.

CodePudding user response：

Either use memcpy or assign each index manually, there is no other sensible solution. You don't have to memcpy the whole array at once, just restrict it to some indices:

memcpy(&values[0], (unsigned char[]){0xAA,0xBB,0xCC,0xDD}, 4);

where values[0] can easily be changed to any values[i]. This is also safe as far as alignment is concerned. Note that there should be no benefit in terms of efficiency between this code and assigning all 4 indices manually. Strive to make the code as readable as possible - if you think compound literals are hard to read for example, then stick to what you already have.