initial commit

c/darts/src/darts.c

@@ -0,0 +1,49 @@
+#include "darts.h"
+
+score_t scores[] ={
+    { 1.0F,  10 },
+    { 25.0F,  5 },
+    { 100.0F, 1 },
+    { -1.0F,  0 }
+};
+
+/* Below function is basically incorrect for general case.
+ * However, it should mostly work here, as we compare relatively small numbers.
+ * see below for better alternatives :
+ * https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
+ */
+static inline bool float_almost_equal(float x, float y)
+{
+    register float f=x-y;
+    return f<MIN_FLOAT_EQUAL && f>-MIN_FLOAT_EQUAL? true: false;
+}
+
+unsigned score(coordinate_t c)
+{
+    float x=c.x, y=c.y, radius=x*x+y*y;
+    int i;
+
+    for (i=0; scores[i].score; ++i) {
+        if (float_almost_equal(radius, scores[i].radius) || radius < scores[i].radius)
+            break;
+    }
+    return scores[i].score;
+}
+
+#ifdef UNIT_TEST
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(int ac, char **av)
+{
+    int arg=1;
+    float x, y;
+
+    for (; arg<ac-1; ++arg, ++arg) {
+        x=atof(av[arg]);
+        y=atof(av[arg+1]);
+        printf("equal(%f, %f)=%d\n", x, y, float_almost_equal(x, y));
+    }
+
+}
+#endif

c/darts/src/darts.h

@@ -0,0 +1,28 @@
+#ifndef DARTS_H
+#define DARTS_H
+
+#include <stdbool.h>
+#include <float.h>
+
+typedef struct {
+    float x, y;
+} coordinate_t;
+
+typedef struct {
+    float radius;
+    int score;
+} score_t;
+
+// to allow float comparisons we consider 2 floats are equal if
+// their difference is below this value.
+// Use: avoid the '<' & '>' which may be wrong.
+#define MIN_FLOAT_EQUAL FLT_EPSILON
+
+extern unsigned score(coordinate_t);
+
+#ifdef TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif