ДЗ № 6.2 Считалочка, Шестаков Николай

src/schitalochka/compilation.md

@@ -0,0 +1,3 @@
+## Сборка:
+gcc -Wall -Wextra -pedantic -O2 -c cyclic_list.c\
+gcc -Wall -Wextra -pedantic -O2 cyclic_list.o main.c

src/schitalochka/cyclic_list.c

@@ -0,0 +1,66 @@
+#include "cyclic_list.h"
+
+#include <stdlib.h>
+
+typedef struct ListElement {
+    int value;
+    struct ListElement* next;
+    struct ListElement* prev;
+} ListElement;
+
+struct List {
+    ListElement* zeroIndexElement;
+    int size;
+};
+
+List* createList(int n)
+{
+    if (n <= 0) {
+        return NULL;
+    }
+
+    ListElement* oldElement = malloc(sizeof(*oldElement));
+    oldElement->value = 1;
+    List* list = malloc(sizeof(*list));
+    list->zeroIndexElement = oldElement;
+    list->size = n;
+    for (int i = 2; i <= n; ++i) {
+        ListElement* newElement = malloc(sizeof(*newElement));
+        newElement->value = i;
+        newElement->prev = oldElement;
+        oldElement->next = newElement;
+        oldElement = newElement;
+    }
+    oldElement->next = list->zeroIndexElement;
+    list->zeroIndexElement->prev = oldElement;
+
+    return list;
+}
+
+void deleteList(List* list)
+{
+    free(list);
+}
+
+int deleteElement(List* list, int index)
+{
+    if (list->zeroIndexElement->next == list->zeroIndexElement) {
+        int value = list->zeroIndexElement->value;
+        free(list->zeroIndexElement);
+        return value;
+    }
+
+    index = index < 0 ? (index % list->size + list->size) : (index % list->size);
+
+    ListElement* currentElement = list->zeroIndexElement;
+    for (int i = 0; i < index; ++i) {
+        currentElement = currentElement->next;
+    }
+    currentElement->prev->next = currentElement->next;
+    currentElement->next->prev = currentElement->prev;
+    list->zeroIndexElement = currentElement->next;
+    list->size--;
+    free(currentElement);
+
+    return 0;
+}

src/schitalochka/cyclic_list.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdbool.h>
+
+typedef struct List List;
+
+// Creates cyclic list with n elements numerated from 1 to n.
+// If n <= 0 returns NULL, else returns pointer on the list.
+// Takes n - count of elements.
+List* createList(int n);
+
+// Deletes the list. The list is assumed to be empty.
+// Takes pointer on the list;
+void deleteList(List* list);
+
+// Deletes element with taken index. Changes index starting pointer on the next element after deleted.
+// Takes pointer on the list and index of the element.
+// Returns 0. If the element is the last returns element.
+int deleteElement(List* list, int index);

src/schitalochka/main.c

@@ -0,0 +1,17 @@
+#include "cyclic_list.h"
+#include <stdio.h>
+
+int main()
+{
+    int peopleCount, everyM;
+    printf("Enter people count and after how many people we kill human (Каждый k+1-ый будет убит) (separated by space): ");
+    scanf("%d %d", &peopleCount, &everyM);
+
+    List* people = createList(peopleCount);
+    int humanNumber = 0;
+    for (; !humanNumber; humanNumber = deleteElement(people, everyM)) { }
+    printf("Number %d is alive! \n", humanNumber);
+
+    deleteList(people);
+    return 0;
+}