different midpoints in C++

midpoints.cpp

int midpointb(int l, int r) {
    return (l + r) >> 1;
}

int midpointw(int l, int r) {
    return l + (r - l) / 2;
}

int midpoint(int l, int r) {
    return static_cast<unsigned int>(l + r) >> 1;
}