Data commit

Task/Continued-fraction/Go/continued-fraction.go

@@ -0,0 +1,53 @@
+package main
+
+import "fmt"
+
+type cfTerm struct {
+    a, b int
+}
+
+// follows subscript convention of mathworld and WP where there is no b(0).
+// cf[0].b is unused in this representation.
+type cf []cfTerm
+
+func cfSqrt2(nTerms int) cf {
+    f := make(cf, nTerms)
+    for n := range f {
+        f[n] = cfTerm{2, 1}
+    }
+    f[0].a = 1
+    return f
+}
+
+func cfNap(nTerms int) cf {
+    f := make(cf, nTerms)
+    for n := range f {
+        f[n] = cfTerm{n, n - 1}
+    }
+    f[0].a = 2
+    f[1].b = 1
+    return f
+}
+
+func cfPi(nTerms int) cf {
+    f := make(cf, nTerms)
+    for n := range f {
+        g := 2*n - 1
+        f[n] = cfTerm{6, g * g}
+    }
+    f[0].a = 3
+    return f
+}
+
+func (f cf) real() (r float64) {
+    for n := len(f) - 1; n > 0; n-- {
+        r = float64(f[n].b) / (float64(f[n].a) + r)
+    }
+    return r + float64(f[0].a)
+}
+
+func main() {
+    fmt.Println("sqrt2:", cfSqrt2(20).real())
+    fmt.Println("nap:  ", cfNap(20).real())
+    fmt.Println("pi:   ", cfPi(20).real())
+}