How do we create a nested linked list? - c

Question

A lecturer teaches 4 different classes.
The number of students in each class may differ from each other.
There are two different linked list structures for holding courses and students.
In the structure of the class (nodeClass), information about which class it is (classID) and the average of the midterm exams of the students in the class (classMidtermAverage) are kept. Besides these, there is a pointer pointing to the next class and a pointer pointing to a node belonging to the structure (nodeStudent) used to define students' information.
In the structure called nodeStudent, there is a student's id, midterm grade and a pointer showing the next student in the same class.
The program takes the student number and midterm grade from the user as input. Students whose student number starts with 66 are in the 1st class, with 77 in the 2nd class, students starting with 88 are in the 3rd class, and students starting with 99 are in the 4th class. Students must appear in the linked list sequentially. Sorting will be done in descending order according to the midterm grade. If the notes are the same, the lower number should be first in the list. The sorted list should be preserved by adding it to the correct location while adding. After all students are added to the list, the midterm average of each class will be calculated and kept in the classMidtermAverage variable of the node generated from the nodeClass structure of the relevant class.
I know we have to create a nested linked list but I am having a hard time inserting the data to the main linked list (being the classes linked list) and the child linked list (students list)
struct nodeClass
{
int classID;
double classMidtermAverage;
struct nodeClass *next;
struct nodeStudent *studentPtr;
};
struct nodeStudent
{
int studentID;
int midterm;
struct nodeStudent *next;
};
struct nodeClass* insert(struct nodeClass **head, int id, int midterm) {
struct nodeStudent* newPtr;
struct nodeClass* temp= (struct nodeClass*) malloc(sizeof(struct nodeClass*));
temp->studentPtr = (struct nodeStudent*) malloc(sizeof(struct nodeStudent));
temp->studentPtr->studentID=id;
temp->studentPtr->midterm=midterm;
long classcode=id;
while (classcode>=100){
classcode=classcode/10;
}
if (classcode=66) {
temp->classID=i;
head=temp;
}
else if( classcode=77) {
temp->classID=2;
head->next=temp;
struct nodeClass* class2= head->next;
}
else if( classcode=88) {
temp->classID=3;
head->next->next=temp;
struct nodeClass* class3= head->next->next;
}
else if( classcode=99) {
temp->classID=4;
head->next->next->next=temp;
struct nodeClass* class3= head->next->next->next;
}
return head;
}
struct nodeClass* computeClassAverage(*head) {
nodeClass* tmp;
for( tmp=head; tmp)
}
void printAll(*head);
and the main function is
#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include "function.h"
int main()
{
struct nodeClass *head = NULL;
int id, midterm;
scanf("%d", &id);
while(id!=-1)
{
scanf("%d", &midterm);
insert(&head, id, midterm);
scanf("%d", &id);
}
computeClassAverage(head);
printAll(head);
return 0;
}

Answer 1

You seem to have some misunderstanding of this subject matter which I can't quite see, so I doubt that this answer will satisfy you, but I'll go out on a limb.
Here is a way to insert new elements into the linked list:
nodeStudent* insertStudent(nodeStudent *head, nodeStudent *newp)
{
newp->next = head;
return newp;
}
nodeClass* insertClass(nodeClass *head, nodeClass *newp)
{
newp->next = head;
return newp;
}
Notice that these functions add the new elements at the head of the list. It is not difficult to write functions to add elements after a given element, or find the end of the list and insert the new element there.