include c:\cxpl\stdlib;

func real NRoot(A, N, Prec);  \Return the Nth root of A with precision Prec
real A;
int N;
real Prec;
real X, X0, Y, NF;
int  I;
[NF:= float(N);
X:= 1.0;               \initial guess
repeat  X0:= X;
        Y:= 1.0;
        for I:= 1 to N-1 do Y:= Y*X0;
        X:= ((NF-1.0)*X0 + A/Y) / NF;
until   abs(X-X0) < Prec;            \(until X=X0 doesn't always work)
return X;
];

[Format(5, 15);
RlOut(0, NRoot( 2., 2, 1.0E-15));  CrLf(0);
RlOut(0, Power( 2., 0.5)); CrLf(0);     \for comparison
RlOut(0, NRoot(27., 3, 1.0E-15));  CrLf(0);
RlOut(0, NRoot(1024., 10, 1.0E-15)); CrLf(0);
]