8Distributions can be parametrized by defining appropriate parameters. For example, uniform_real_distribution<double> drandom(a   ,b   ) produces numbers in the [a,b)  interval, normal_distribution <double> gaussran(μ   ,σ   ) produces numbers distributed according to exp[− (x− μ)2∕(2σ2)]∕(σ√2π)  etc. If the parameters are omitted, then they take default values (here a  =0, b  =1, μ  =0, σ  =1)