usaa24/cv6/a_station.c

#include "a_train.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct car* add_car(struct car* first, const char* target) {
    struct car* last = first;
    struct car* newcar = calloc(1, sizeof(struct car));
    strcpy(newcar->value, target);

    if (last != NULL) {
        struct car* current = last;
        while (current->next != NULL) {
            current = current->next;
        }
        current->next = newcar;
    } else {
        last = newcar;
        return last;
    }

    return first;
}

void print_train(struct car* first) {
    if(first != NULL){
        struct car* current = first;
        while(current->next != NULL){
            printf("%s\n", current->value);
            current = current->next;
        }
    }
}

void cancel_train(struct car* first) {
    struct car* current = first;
    while(first != NULL){
        current = current->next;
        free(first);
        first = current;
    }
}


struct car* clear_train(struct car* first, const char* target) {
    if (first == NULL) {
        return NULL;
    }

    struct car* current = first;
    struct car* previous = NULL;

    while (current != NULL && strcmp(current->value, target) == 0) {
        struct car* temp = current;
        first = current->next;
        current = first;
        free(temp);
    }

    while (current != NULL) {
        if (strcmp(current->value, target) == 0) {
            previous->next = current->next;
            free(current);
            current = previous->next;
        } else {
            previous = current;
            current = current->next;
        }
    }

    return first;
}