Data commit

Task/Nth-root/Icon/nth-root.icon

@@ -0,0 +1,23 @@
+procedure main()
+   showroot(125,3)
+   showroot(27,3)
+   showroot(1024,10)
+   showroot(39.0625,4)
+   showroot(7131.5^10,10)
+end
+
+procedure showroot(a,n)
+   printf("%i-th root of %i = %i\n",n,a,root(a,n))
+end
+
+procedure root(a,n,p) #: finds the n-th root of the number a to precision p
+   if n < 0 | type(n) !== "integer" then runerr(101,n)
+   if a < 0 then runerr(205,a)
+   /p := 1e-14                  # precision
+   xn := a / real(n)            # initial guess
+   while abs(a - xn^n) > p do
+      xn := ((n - 1) * (xi := xn) + a / (xi ^ (n-1))) / real(n)
+   return xn
+end
+
+link printf