Counter Problems and Segmentation Fault (Core Dumped) in C - c

Question

I am currently coding in C and am having trouble trying to selectively search through a linked list of movie information/rating structs. So far I've just gotten a segmentation fault core dump. My current algorithm basically while loops current = current->next except until it reaches NULL in the linked list. It prints out the movie details (through show_structure()) if the user input matches the title information in the linked list.
But to be honest, I want to be able to solve this problem while also implementing where if the user types in a movie title that is not in the linked list it would print out: " Movie does not exist in the database."
Also somehow the counter doesn't increment when I update new movies into the linked list. It keeps staying at 1. Any ideas?
This is my code so far:
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
struct movie_node {
char title[250];
int year;
unsigned char rating;
struct movie_node *next;
};
typedef struct movie_node movie_t;
movie_t *first;
movie_t *current;
movie_t *new;
movie_t *make_structure(void);
void fill_structure(movie_t *a);
void show_structure(movie_t *a);
int main()
{
int counter = 0;
char traverse = 1;
char maininput[1];
char searchinput[250];
while (traverse)
{
printf("%d Movie(s) in the database. Update, Search, or Quit (U/S/Q): ", counter);
scanf("%1s", maininput);
if (strcmp("U", maininput) == 0)
{
if (counter == 0)
{
first = make_structure();
current = first;
}
else
{
new = make_structure();
current->next=new;
current=new;
}
counter++; //COUNTER DOESN'T INCREMENT
fill_structure(current);
current->next = NULL;
printf("Movie %s is added to the database.\n\n", current->title);
}
if (strcmp("S", maininput) == 0)
{
printf("Name of the movie: ");
scanf(" %[^\n]%*c", searchinput);
current = first;
do
{
current=current->next;
if (strcmp(searchinput, current->title) == 0) //PROBLEM LIES HERE
{show_structure(current);}
} while(current != NULL);
}
if (strcmp("Q", maininput) == 0)
{
traverse = 0;
}
}
return 0;
}
movie_t *make_structure(void)
{
movie_t *a;
a = (movie_t *)malloc(sizeof(movie_t));
return a;
}
void fill_structure(movie_t *a)
{
printf("Name of the movie: ");
scanf(" %[^\n]%*c", a->title);
printf("Year: ");
scanf("%d", &a->year);
printf("Rating: ");
scanf("%hhu", &a->rating);
}
void show_structure(movie_t *a)
{
printf("Year: %d ", a->year);
printf("Rating: %hhu", a->rating);
}
Output is like this right now:
0 Movie(s) in the database. Update, Search, or Quit (U/S/Q): U
Name of the movie: Pulp Fiction
Year: 1994
Rating: 5
Movie Pulp Fiction is added to the database.
1 Movie(s) in the database. Update, Search, or Quit (U/S/Q): U
Name of the movie: Forrest Gump
Year: 1994
Rating: 5
Movie Forrest Gump is added to the database.
1 Movie(s) in the database. Update, Search, or Quit (U/S/Q): S
Name of the movie: Pulp Fiction
Segmentation fault (core dumped)

Answer 1

Think about this code:
do
{
current=current->next;
if (strcmp(searchinput, current->title) == 0) //PROBLEM LIES HERE
{show_structure(current);}
} while(current != NULL);
When current is the last element, it is not null. You enter the top of the loop, set current to current->next, which is null, and then try to access current->title. But current is NULL. That is a problem. This would be better:
current = first;
while(current != NULL) {
if (strcmp(searchinput, current->title) == 0)
show_structure(current);
current=current->next;
}

Answer 2

this
char maininput[1];
and this
scanf("%1s", maininput);
do not work well with each other.
a %s is a number of characters ending in a \0 so when you write %1s you are expecting at least 2 characters.
instead use fgetc(stdin) to read one character from console.