usaa24/cv4/a_train.c

#include <stdio.h>
#define SIZE 50


struct car
{
    char value[SIZE]; // Cieľová stanica
    struct car* next; // Ďaľší záznam, môže byť NULL
};

struct car* add_car(struct car* first,const char* target)
{
    struct car* nc=(struct car*) malloc(sizeof(struct car));
    strcpy(nc->value, target);
    nc->next=NULL;

    if(first)
    {
        while(first->next!=NULL)
        {    
            first=first->next;
        }
        first->next=nc;
        return first;
    }
    
    first=nc;  

    return first;
}

void print_train(struct car* first)
{
    if(first==NULL)
    {
        return;
    }

    do
    {
        printf("%s -> ", first->value);
        first=first->next;
    }while(first->next!=NULL);

}

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

struct car* clear_train(struct car* first, const char* target)
{
    struct car* t;  //змінна для збереження кого видаляти

    if(first==NULL || target==NULL)
    {
        return first;
    }

    //голова == таргет - видаляємо лише перший
    while(strcmp(first->value, target)==0) //поки рядки однакові
    {
        t=first;
        first=first->next;
        free(t);
        if(first==NULL)
        {
           return NULL;
        }
    }

    //голова не  таргет
    do
    {
        if(strcmp(first->next->value, target)==0)
        {
            t=first;
            first=first->next;
            free(t);
        }
        else
        {
            first=first->next;
        }
    }
    while(first);
	return first;
}

int main()
 {
  struct car* train = NULL;
  train = add_car(train,"Presov");
  train = add_car(train,"Bratislava");
  train = add_car(train,"Levoca");
  train = add_car(train,"Spiska Nova Ves");
  print_train(train);
  clear_train(train,"Levoca");
  print_train(train);
  cancel_train(train);
  return 0;
}