Looking to store an int in a char array via its equivalent ascii value in C

As above, I'm calculating some numbers, (inbetween 0 and 255) and I'm wanting to store them in a char array in C using their ASCII equivalents.

Is there a nice way of doing this?

int b = (int)(*pixelA.pixel_b * (1-w) * (1-h) + *pixelB.pixel_b * (w) * (1-h) + *pixelC.pixel_b * (1-w) * (h) + *pixelD.pixel_b * (w*h));

        modified_Frame[k] = (char)b;

That's the kind of thing I'm aiming for, if the (char) meant it took the value of b, and wrote the ASCII equivalent into the array.

I tried using both pointers (hoping the C would just do it automatically) like so:

int *pb = &b;   
modified_Frame[k] = *pb;

And using chars for b rather than an int, however it just seems to send block data back, so I'm guessing it doesn't work how I'm intending it to.

Any ideas would be greatly appreciated.