Praxis der Programmierung 2020 Hausaufgabe

main.c

#include <stdlib.h>
#include <stdio.h>

#define cr printf("\n")

struct le
{
    int value;
    struct le *next;
};

typedef struct le listelement;
typedef listelement *list;

void insert(int v, list *l)
{
    listelement *new;
    new = malloc(sizeof(listelement));
    new->value = v;
    new->next = *l;
    *l = new;
}

void print_list(list l)
{
    if (l == NULL)
    {

        printf("leer");
        return;
    }

    while (l != NULL)
    {
        printf("%d ", l->value);
        l = l->next;
    }
}

void delete_all(list *l)
{
    list next;
    while (*l != NULL)
    {
        next = (*l)->next;
        free(*l);
        *l = next;
    }
}

int length(list l)
{
    int count = 0;
    while (l != NULL)
    {
        count++;
        l = l->next;
    }
    return count;
}

int delete_head(list *l)
{
    if (*l == NULL)
        return -1;

    list old = *l;
    *l = old->next;
    free(old);

    return 0;
}

int contains(int v, list l)
{
    listelement *current = l;
    int counter = 0;

    while (current != NULL)
    {
        if (current->value == v)
            return counter;

        current = current->next;
        counter++;
    }

    return -1;
}

int insert_pos(int v, int pos, list *l)
{
    listelement *previous = NULL;
    listelement *current = *l;
    int counter = 0;

    // Wrong index
    if (pos < 0)
        return -1;

    while (current != NULL)
    {
        if (counter == pos)
        {
            listelement *new;
            new = malloc(sizeof(listelement));
            new->value = v;
            new->next = current;

            if (counter == 0)
                *l = new;
            else
                previous->next = new;

            return 0;
        }

        previous = current;
        current = current->next;
        counter++;
    }

    return -1;
}

list reverse(list l)
{
    listelement *previous = NULL;
    listelement *current = l;
    listelement *next = NULL;

    while (current != NULL)
    {
        next = current->next;

        current->next = previous;

        previous = current;
        current = next;
    }

    return previous;
}

int main()
{
    list l = NULL;

    insert(3, &l);
    insert(0, &l);
    insert(1, &l);
    insert(2, &l);
    insert(3, &l);
    print_list(l);
    delete_head(&l);
    print_list(l);
    cr;

    printf("43 inserted: %d", insert_pos(43, 1, &l));
    cr;
    print_list(l);
    cr;
    printf("77 inserted: %d", insert_pos(77, 500, &l));
    cr;

    printf("Length: %d", length(l));
    cr;

    printf("Contains 44:  %d", contains(44, l));
    cr;
    printf("Contains 43: %d", contains(43, l));
    cr;
    printf("Contains 3: %d", contains(3, l));
    cr;

    printf("Reverse:\n");
    print_list(l);
    cr;
    print_list(reverse(l));
    cr;

    printf("Delete all: ");
    delete_all(&l);
    print_list(l);
}