Initial data commit

Task/Sorting-algorithms-Cocktail-sort/C/sorting-algorithms-cocktail-sort-1.c

@@ -0,0 +1,39 @@
+#include <stdio.h>
+
+// can be any swap function. This swap is optimized for numbers.
+void swap(int *x, int *y) {
+	if(x == y)
+		return;
+	*x ^= *y;
+	*y ^= *x;
+	*x ^= *y;
+}
+void cocktailsort(int *a, size_t n) {
+	while(1) {
+		// packing two similar loops into one
+		char flag;
+		size_t start[2] = {1, n - 1},
+			   end[2] = {n, 0},
+			   inc[2] = {1, -1};
+		for(int it = 0; it < 2; ++it) {
+			flag = 1;
+			for(int i = start[it]; i != end[it]; i += inc[it])
+				if(a[i - 1] > a[i]) {
+					swap(a + i - 1, a + i);
+					flag = 0;
+				}
+			if(flag)
+				return;
+		}
+	}
+}
+
+int main(void) {
+	int a[] = { 5, -1, 101, -4, 0, 1, 8, 6, 2, 3 };
+	size_t n = sizeof(a)/sizeof(a[0]);
+
+	cocktailsort(a, n);
+	for (size_t i = 0; i < n; ++i)
+		printf("%d ", a[i]);
+	return 0;
+}

Task/Sorting-algorithms-Cocktail-sort/C/sorting-algorithms-cocktail-sort-2.c

@@ -0,0 +1 @@
+-4 -1 0 1 2 3 5 6 8 101

Task/Sorting-algorithms-Cocktail-sort/C/sorting-algorithms-cocktail-sort-3.c

@@ -0,0 +1,64 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+void swap(char* p1, char* p2, size_t size) {
+    for (; size-- > 0; ++p1, ++p2) {
+        char tmp = *p1;
+        *p1 = *p2;
+        *p2 = tmp;
+    }
+}
+
+void cocktail_sort(void* base, size_t count, size_t size,
+                   int (*cmp)(const void*, const void*)) {
+    char* begin = base;
+    char* end = base + size * count;
+    if (end == begin)
+        return;
+    bool swapped = true;
+    for (end -= size; swapped; ) {
+        swapped = false;
+        for (char* p = begin; p < end; p += size) {
+            char* q = p + size;
+            if (cmp(p, q) > 0) {
+                swap(p, q, size);
+                swapped = true;
+            }
+        }
+        if (!swapped)
+            break;
+        swapped = false;
+        for (char* p = end; p > begin; p -= size) {
+            char* q = p - size;
+            if (cmp(q, p) > 0) {
+                swap(p, q, size);
+                swapped = true;
+            }
+        }
+    }
+}
+
+int string_compare(const void* p1, const void* p2) {
+    const char* const* s1 = p1;
+    const char* const* s2 = p2;
+    return strcmp(*s1, *s2);
+}
+
+void print(const char** a, size_t len) {
+    for (size_t i = 0; i < len; ++i)
+        printf("%s ", a[i]);
+    printf("\n");
+}
+
+int main() {
+    const char* a[] = { "one", "two", "three", "four", "five",
+        "six", "seven", "eight", "nine", "ten" };
+    const size_t len = sizeof(a)/sizeof(a[0]);
+    printf("before: ");
+    print(a, len);
+    cocktail_sort(a, len, sizeof(char*), string_compare);
+    printf("after: ");
+    print(a, len);
+    return 0;
+}