Add all the A tasks

Task/Averages-Simple-moving-average/C/averages-simple-moving-average-1.c

@@ -0,0 +1,69 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+typedef struct sma_obj {
+  double sma;
+  double sum;
+  int period;
+  double *values;
+  int lv;
+} sma_obj_t;
+
+typedef union sma_result {
+  sma_obj_t *handle;
+  double sma;
+  double *values;
+} sma_result_t;
+
+enum Action { SMA_NEW, SMA_FREE, SMA_VALUES, SMA_ADD, SMA_MEAN };
+sma_result_t sma(enum Action action, ...)
+{
+  va_list vl;
+  sma_result_t r;
+  sma_obj_t *o;
+  double v;
+
+  va_start(vl, action);
+  switch(action) {
+  case SMA_NEW: // args: int period
+    r.handle = malloc(sizeof(sma_obj_t));
+    r.handle->sma = 0.0;
+    r.handle->period = va_arg(vl, int);
+    r.handle->values = malloc(r.handle->period * sizeof(double));
+    r.handle->lv = 0;
+    r.handle->sum = 0.0;
+    break;
+  case SMA_FREE: // args: sma_obj_t *handle
+    r.handle = va_arg(vl, sma_obj_t *);
+    free(r.handle->values);
+    free(r.handle);
+    r.handle = NULL;
+    break;
+  case SMA_VALUES: // args: sma_obj_t *handle
+    o = va_arg(vl, sma_obj_t *);
+    r.values = o->values;
+    break;
+  case SMA_MEAN: // args: sma_obj_t *handle
+    o = va_arg(vl, sma_obj_t *);
+    r.sma = o->sma;
+    break;
+  case SMA_ADD: // args: sma_obj_t *handle, double value
+    o = va_arg(vl, sma_obj_t *);
+    v = va_arg(vl, double);
+    if ( o->lv < o->period ) {
+      o->values[o->lv++] = v;
+      o->sum += v;
+      o->sma = o->sum / o->lv;
+    } else {
+      o->sum -= o->values[ o->lv % o->period];
+      o->sum += v;
+      o->sma = o->sum / o->period;
+      o->values[ o->lv % o->period ] = v; o->lv++;
+    }
+    r.sma = o->sma;
+    break;
+  }
+  va_end(vl);
+  return r;
+}

Task/Averages-Simple-moving-average/C/averages-simple-moving-average-2.c

@@ -0,0 +1,18 @@
+double v[] = { 1, 2, 3, 4, 5, 5, 4, 3, 2, 1 };
+
+int main()
+{
+  int i;
+
+  sma_obj_t *h3 = sma(SMA_NEW, 3).handle;
+  sma_obj_t *h5 = sma(SMA_NEW, 5).handle;
+
+  for(i=0; i < sizeof(v)/sizeof(double) ; i++) {
+    printf("next number %lf, SMA_3 = %lf, SMA_5 = %lf\n",
+	   v[i], sma(SMA_ADD, h3, v[i]).sma, sma(SMA_ADD, h5, v[i]).sma);
+  }
+
+  sma(SMA_FREE, h3);
+  sma(SMA_FREE, h5);
+  return 0;
+}