Doubly linked list delete last C - c

Question

Im working on a implementation of a doubly linked list. I want the linked list to be limited by some length. When the list becomes longer then delete the last node. Im having some problems here. I want to define tail so that i dont have to search for the end. Here is the implementation i am working on it will allow for a length of 4 then start deleting the last node.
/* Doubly Linked List implementation */
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
struct Node {
char command[1024];
struct Node* next;
struct Node* prev;
};
struct Node* head; //global pointing to head
struct Node* tail; //global pointing to tail
//Creates a new Node and returns pointer to it.
struct Node* GetNewNode(char *line) {
struct Node* newCommand = (struct Node*)malloc(sizeof(struct Node));
int i = 0;
while(line[i] != '\0'){
newCommand->command[i] = line[i];
i++;
}
newCommand->prev = NULL;
newCommand->next = NULL;
return newCommand;
}
//Inserts a Node at head of doubly linked list
void InsertAtHead(char *line) {
struct Node* newCommand = GetNewNode(line);
if(head == NULL) {
head = newCommand;
tail = newCommand;
return;
}
head->prev = newCommand;
newCommand->next = head;
head = newCommand;
}
//Use tail to delete the last node
void deleteLast(){
struct Node* temp = tail;
tail = temp->prev;
free(tail->next);
tail->next = NULL;
}
//Print in reverse orer
void Print() {
struct Node* temp = tail;
while(temp != NULL) {
printf("%s \n",temp->command);
temp = temp->prev;
}
}
int main() {
int numNodes = 0;
char line[1024];
head = NULL;
tail = NULL; // empty list. set head/tail as NULL.
printf("next node: ");
while (fgets(line, 1024, stdin)) {
line[strlen(line)-1] = '\0';
if(numNodes == 4){
numNodes -= 1;
deleteLast();
}
InsertAtHead(line);Print();
numNodes += 1;
printf("next node: ");
}
Print();
}
it seems to be deleting the last node but printing some weird symbols after. Im guessing that its a problem with how i free() but i cant figure it out.
note some of this code is taken from https://gist.github.com/mycodeschool/7429492

Answer 1

Your code looks fine, hoewever, there is an error in copying the command to the node:
while(line[i] != '\0'){
newCommand->command[i] = line[i];
i++;
}
should be:
while(line[i] != '\0'){
newCommand->command[i] = line[i];
i++;
}
newCommand->command[i] = '\0';
(You forgot to terminate the copied command.)
Note also that you must check not to go beyond available space, e.g.:
while(i<1023 && line[i] != '\0'){
newCommand->command[i] = line[i];
i++;
}
newCommand->command[i] = '\0';