usaa20/cv6/a_station.c

150 lines
2.0 KiB
C

#include "a_station.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int getLength(struct car* first) {
if (first != NULL) {
int count = 1;
while (first->next != NULL) {
count++;
first = first->next;
}
return count;
} else {
return 0;
}
}
struct car* getLast(struct car* first) {
if (first == NULL) return NULL;
while (first->next != NULL) first = first->next;
return first;
}
struct car* getLastButOne(struct car* first) {
if (first == NULL || first->next == NULL) return NULL;
while (first->next->next != NULL) first = first->next;
return first;
}
struct car* add_car(struct car* first, const char* target) {
struct car* newcar = calloc(1,sizeof(struct car));
strcpy(newcar->value, target);
newcar->next = NULL;
if (first == NULL) return newcar;
struct car* last = getLast(first);
last->next = newcar;
return first;
}
void print_train(struct car* first) {
if (first == NULL) return;
struct car* this = first;
printf("\nTrain way:\n\n");
printf("%s", this->value);
while (this->next != NULL) {
this = this->next;
printf(" -> ");
printf("%s", this->value);
}
printf("\n\n");
}
void popBack(struct car* first) {
if (first == NULL) { printf("123"); return; }
struct car* lastbo = getLastButOne(first);
if (lastbo == NULL) {
free(first);
first = NULL;
} else {
free(lastbo->next);
lastbo->next = NULL;
}
}
void cancel_train(struct car* first) {
if (first == NULL) return;
while (first->next != NULL) popBack(first);
free(first);
first = NULL;
}
struct car* clear_train(struct car* first, const char* target) {
if (first == NULL) return NULL;
// while (first->next->next != NULL) {
// if (strcmp(first->next->value, target) == 0) {
// struct car* node = first->next->next;
// free(first->next);
// first->next = node;
// }
// }
struct car* this = first;
if (strcmp(first->value, target) == 0) {
this = this->next;
free(first);
}
return this;
}