1 files changed, 116 insertions, 0 deletions
diff --git a/linked_list.c b/linked_list.c
new file mode 100644
index 0000000..0a730d6
--- /dev/null
+++ b/linked_list.c
@@ -0,0 +1,116 @@
+#include "linked_list.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+void append(struct list_item *first, int x) {
+    // find the last element
+    struct list_item *current = first;
+    while (current->next) {
+        current = current->next;
+    }
+    // insert after
+    struct list_item *new = malloc(sizeof(struct list_item));
+    new->value = x;
+    new->next = NULL;
+    current->next = new;
+}
+
+void prepend(struct list_item *first, int x) {
+    // the first element is a head-element so we insert after it
+    struct list_item *new = malloc(sizeof(struct list_item));
+    new->value = x;
+    new->next = first->next;
+    first->next = new;
+}
+
+void print(struct list_item *first) {
+    // skip printing the head
+    struct list_item *current = first->next;
+    while (current) {
+        printf("%d ", current->value);
+        current = current->next;
+    }
+    printf("\n");
+}
+
+void input_sorted(struct list_item *first, int x) {
+    struct list_item *current = first;
+    // find the first element in the list larger than x
+    // (we check current->next since we want to insert after current)
+    // if we reach the end (!current->next) we insert after current
+    while (current->next && current->next->value <= x) {
+        current = current->next;
+    }
+    struct list_item *new = malloc(sizeof(struct list_item));
+    new->value = x;
+    new->next = current->next;
+    current->next = new;
+}
+
+void clear(struct list_item *first) {
+    // don't clear head
+    struct list_item *current = first->next;
+    if (!current) {
+        // empty list, don't free anything
+        return;
+    }
+    struct list_item *next;
+    while (current) {
+        next = current->next;
+        free(current);
+        current = next;
+    }
+    first->next = NULL;
+}
+
+int main(int argc, char **argv) {
+    // head element
+    struct list_item root;
+    root.value = -1;
+    root.next = NULL;
+
+    // empty clears
+    clear(&root);
+    clear(&root);
+    print(&root);
+
+    // short append
+    append(&root, 1);
+    append(&root, 2);
+    append(&root, 3);
+    print(&root);
+    clear(&root);
+
+    // short prepend
+    prepend(&root, 1);
+    prepend(&root, 2);
+    prepend(&root, 3);
+    print(&root);
+    clear(&root);
+
+    // mix append prepend
+    append(&root, 1);
+    append(&root, 2);
+    prepend(&root, 4);
+    append(&root, 3);
+    prepend(&root, 5);
+    print(&root);
+    clear(&root);
+
+    //// input_sorted
+    append(&root, 10);
+    append(&root, 20);
+    append(&root, 30);
+    print(&root);
+    // in the middle
+    input_sorted(&root, 15);
+    input_sorted(&root, 25);
+    // at the back (new largest element)
+    input_sorted(&root, 35);
+    // at the front
+    input_sorted(&root, 5);
+    print(&root);
+    clear(&root);
+    print(&root);
+}