C++ - Bit-wise not of uchar produces int

Question

I am surprised by C++\'s behavior when applying bit-wise not to an unsigned char.

Take the binary value 01010101b, which is 0x55, or

Answer 1

You can kind of "truncate" the leading 1's by assigning the result of ~0x55 to an unsigned char:

#include 

int main()
{
    unsigned char input = 0x55;
    unsigned char output = ~input;

    std::cout << "input: " << (int)input << " output: " << (int)output << std::endl;

    return 0;
}

Result:

input: 85 output: 170