Data commit

Task/Order-by-pair-comparisons/C/order-by-pair-comparisons.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+int interactiveCompare(const void *x1, const void *x2)
+{
+  const char *s1 = *(const char * const *)x1;
+  const char *s2 = *(const char * const *)x2;
+  static int count = 0;
+  printf("(%d) Is %s <, ==, or > %s? Answer -1, 0, or 1: ", ++count, s1, s2);
+  int response;
+  scanf("%d", &response);
+  return response;
+}
+
+void printOrder(const char *items[], int len)
+{
+  printf("{ ");
+  for (int i = 0; i < len; ++i) printf("%s ", items[i]);
+  printf("}\n");
+}
+
+int main(void)
+{
+  const char *items[] =
+    {
+      "violet", "red", "green", "indigo", "blue", "yellow", "orange"
+    };
+
+  qsort(items, sizeof(items)/sizeof(*items), sizeof(*items), interactiveCompare);
+  printOrder(items, sizeof(items)/sizeof(*items));
+  return 0;
+}