May 11
uint buildIP(ubyte a, ubyte b, ubyte c, ubyte d)
{
    uint r = 0;
    r  = a << 24;
    r |= b << 16;
    r |= c << 8;
    r |= d;
    return r;
}

string toString(uint ip)
{
    import std.conv : to;
    string s;

    s ~= to!string(ip >> 24) ~ ".";
    s ~= to!string(0xff & ip >> 16) ~ ".";
    s ~= to!string(0xff & ip >> 8) ~ ".";
    s ~= to!string(0xff & ip);
    return s;
}

void main()
{
    import std.stdio;
    auto ip = buildIP(222, 31, 224, 172);
    toString(ip).writeln;
}