#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* newcar = calloc(1,sizeof(struct car));
	if(!newcar) return first;

	strcpy(newcar->value, target);
	newcar->next = NULL;

	if(first == NULL){
		return newcar;
	}
	struct car* temp = first;
	while(temp->next !=NULL){
		temp = temp->next;
	}
	temp->next = newcar;
      	return first;
}

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

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


struct car* clear_train(struct car* first, const char* target) {
	struct car* temp = first;
	struct car* prev = NULL;

	while(temp != NULL){
		if(strcmp(temp->value, target)== 0){
		if(prev == NULL){
			first= temp->next;
			free(temp);
			temp= first;

		}else{
			prev->next= temp->next;
			free(temp);
			temp = prev->next;
		}
	}else{
		prev= temp;
		temp =temp->next;	
	}
	}
	return first;
}