Data commit

Task/Continued-fraction/D/continued-fraction.d

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+import std.stdio, std.functional, std.traits;
+
+FP calc(FP, F)(in F fun, in int n) pure nothrow if (isCallable!F) {
+    FP temp = 0;
+
+    foreach_reverse (immutable ni; 1 .. n + 1) {
+        immutable p = fun(ni);
+        temp = p[1] / (FP(p[0]) + temp);
+    }
+    return fun(0)[0] + temp;
+}
+
+int[2] fSqrt2(in int n) pure nothrow {
+    return [n > 0 ? 2 : 1,   1];
+}
+
+int[2] fNapier(in int n) pure nothrow {
+    return [n > 0 ? n : 2,   n > 1 ? (n - 1) : 1];
+}
+
+int[2] fPi(in int n) pure nothrow {
+    return [n > 0 ? 6 : 3,   (2 * n - 1) ^^ 2];
+}
+
+alias print = curry!(writefln, "%.19f");
+
+void main() {
+    calc!real(&fSqrt2, 200).print;
+    calc!real(&fNapier, 200).print;
+    calc!real(&fPi, 200).print;
+}