qutab

enp100s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.168.49.139  netmask 255.255.255.0  broadcast 10.168.49.255
        inet6 fe80::7e31:2284:8ad9:49b4  prefixlen 64  scopeid 0x20<link>
        ether 48:21:0b:3b:f3:b1  txqueuelen 1000  (Ethernet)
        RX packets 189705745  bytes 18263493521 (18.2 GB)
        RX errors 0  dropped 71100073  overruns 0  frame 0
        TX packets 3881555  bytes 876404986 (876.4 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device memory 0x84200000-842fffff  

qutab

void square(std::vector<double>& v)
{
    std::transform(v.begin(), v.end(), v.begin(), [](double d) { return d*d; });
}
 
double rms(std::vector<double>& v)
{
    square(v);
    double the_mean = mean(v);
    double the_rms = std::sqrt(the_mean);