function to delete elements selected linked list C - c

Question

Hi I'm creating a program for school where I have to:
Create structures
Create functions to print my linked list
Create functions to insert an ordered element
Delete elements with a minor year less than the year selected
I created all a part the last one step.
Can you help me to know what is the right way?
This is my code:
STRUCTURE:
typedef struct dimension {
int height;
int length;
} DIMENSION;
typedef struct pic {
DIMENSION d;
char name[50];
int year;
} PIC;
typedef struct node {
PIC p;
struct node *next;
} NODE;
PRINT LIST:
void printPic(PIC p) {
printf("Autor: %s\nDimension\nHeight: %d\nLength: %d\nYear: %d\n", p.name, p.d.height, p.d.length, p.year);
}
void printList(NODE *head) {
if(head->next==NULL) {
printf("No element in the list!\n");
} else {
while(head->next != NULL) {
head = head->next;
printPic(head->p);
}
}
}
NEW PIC(ORDERED WITH AREA DIMENSION)
int area(PIC p) {
return (p.d.height * p.d.length);
}
PIC createPic() {
PIC newPic;
printf("Author: ");
fgets(newPic.name, 50, stdin);
newPic.name[strlen(newPic.name)-1] = '\0';
printf("Height: ");
scanf("%d", &newPic.d.height);
printf("\n");
printf("Length: ");
scanf("%d", &newPic.d.length);
printf("\n");
printf("Year: ");
scanf("%d", &newPic.year);
printf("\n");
printf("\n");
return newPic;
}
void insertPic(NODE *head) {
NODE* newNode = malloc(sizeof(NODE));
newNode->p = createPic();
newNode->next = NULL;
if(head==NULL) {
head = newNode;
} else {
if(area(newNode->p) < area(head->p)) {
newNode->next = head;
head = newNode;
} else {
while(head->next != NULL && (area(newNode->p) > area(head->next->p))) {
head = head->next;
}
newNode->next = head->next;
head->next = newNode;
}
}
}
DELETE ELEMENTS WITH A MINOR YEAR THAN SELECTED YEAR:
Edited and now it works:
void deletePic(NODE *head, int year) {
if(head==NULL) {
printf("No element in the list!\n");
} else {
while(head->next != NULL) {
if(head->next->p.year < year) {
NODE *p = head->next;
head->next = p->next;
free(p);
} else {
head = head->next;
}
}
}
}
MAIN:
int main() {
NODE *head = malloc(sizeof(NODE));
head->next = NULL;
int choice = -1;
while(choice != 0) {
printf("Select an action:\n");
printf("Press 1 --> See list\n");
printf("Press 2 --> Insert a new element\n");
printf("Press 3 --> Delete elements with a minor year\n");
printf("Press 0 --> Stop program\n");
scanf("%d%*c", &choice);
if(choice==1) {
printList(head);
}
else if(choice==2) {
insertPic(head);
}
else if(choice==3) {
int year;
printf("Choose an year\nAll elements with a smaller year will be eliminated\n");
scanf("%d", &year);
deletePic(head, year);
}
else if(choice==0) {
printf("See you soon ;)\n");
}
}
}

Answer 1

Your deletePic function is broken in multiple places. Among them:
Dereferencing an indeterminate pointer, yearNode
Incorrect comparator (should use < ; not !=
free'ing an indeterminate pointer.
The first and last of those are a recipe for disaster. If that function does what the menu claims it should, I think what you want is this:
void deletePic(NODE *head, int year)
{
if (head == NULL)
{
printf("No element in the list!\n");
}
else
{
while (head->next != NULL)
{
if (head->next->p.year < year)
{
NODE *p = head->next;
head->next = p->next;
free(p);
}
else
{
head = head->next;
}
}
}
}