RosettaCodeData/Task/Nth-root/S-BASIC/nth-root-2.basic

rem - return the nth root of x to stated precision
function nthroot(n, x, precision = real.double) = real.double
   var x0, x1 = real.double
   x0 = x
   x1 = x / n         rem - initial guess
   while abs(x1 - x0) > precision do
      begin
        x0 = x1
        x1 = ((n-1.0) * x1 + x / x1 ^ (n-1.0)) / n
      end
end = x1

rem -- exercise the routine

var i = integer
var x = real.double

x = 144
print "Finding the nth root of"; x; " to 8 decimal places"
print "  x      n        root"
print "------------------------"
for i = 2 to 8
   print using "###   ####    ###.########"; x; i; nthroot(i, x, 1E-9)
next i

end