linked list inside a linked list (nested linked list)

Question

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>



  struct module {

 char name[10];
  int note;
  struct module * next;

    };
  typedef struct module module;


  struct student {
  char name[10];
  char adress[20];
  struct student * next;
  module * head;

 } ;
 typedef struct student student;


 student *etudiant=NULL;



  module* add_module(char name[],int note){
module *p=(module*)malloc(sizeof(module));
p->note=note;
p->next=NULL;
strcpy(p->name,name);

return p;
 }



 void add_student(char name[], char adress[])

 {

     student *p=(student*)malloc(sizeof(student));
     strcpy(p->name,name);
     strcpy(p->adress,adress);

     p->head= add_module("algo",15);
     p->next=NULL;

     if (etudiant==NULL){

    etudiant=p;
}
else{
    student *q = etudiant;

while(q->next!=NULL){

    q=q->next;

     }
     q->next=p;
          }
 }


    void print_module(module *m){

 if (m==NULL)
 {
     printf("NULL");


 }
 else
 {
     while(m->next!=NULL){
         printf("%s   ",m->name);
    printf("%d\n",m->note);
    m=m->next;
     }

 }


}


 void print(){
 student *p;
 module *m;
 p = etudiant;
 if (etudiant==NULL){

printf("NULL");
 }

 else
 {
while (p->next!=NULL);
 {
     printf("%s   ",etudiant->name);
     printf("%s   ",etudiant->adress);

     m = p->head;
     while(m != NULL){
        printf("%s ",m->name);
        printf("%d ",m->note);
        m= m->next;
     }
     p = p->next;
      }
 }


 }

int main () {

    add_student("jack","nowhere");
    print();

    return 0;
}

What I want to create is a list inside a list exemple

  Student list :

  Student || subject || ==> student 2 || subject
          |                          |
          maths                      POO
          |                          |
          physiques                 English

that's an approximate paiting of my structure, i arrived to add one subject to one student, but i don't know how to add more. thanks in advance.

I defined the student list as a global one since i would be needing only one list containing all students

traverse the student list and find the student to which you want to add the module, then just traverse its module list and add the module to its module list. — Rajeev Singh
– Rajeev Singh, Commented Nov 15, 2016 at 19:42
@rajev how ? sean i don't know if i get u well, but every student have a linked list of subjects. — Mouttie Dje
– Mouttie Dje, Commented Nov 15, 2016 at 19:44

Rajeev Singh · Accepted Answer · 2016-11-15 21:31:38Z

1

Let this is your student list :

Student1 ==> student2 ==> NULL
   |            |
   maths        POO
   |            |
   physiques    English

Now if you want to add module "Computer Science" to student2 then you have to do the following steps:

traverse the student list to find the student2.
then traverse its module list.
add module "Computer Science" to list(you can add anywhere as per your requirement).

Your function will be like this:

typedef struct student student;
void addModule(char studentName[], char subject[], int note) {
    // searching student in the list..
    if(etudiant != NULL) {
        struct student *s = etudiant; //start of the list
        while(s && strcmp(s->name, studentName) != 0)
            s = s->next;

        if(s != NULL) {
            // creating module...
            module* new = (module*)malloc(sizeof(module));
            strcpy(new->name, subject);
            new->note = note;
            new->next = NULL;

            //adding module to the front of the module list of student s ...
            module* tmp = s->head;
            s->head = new;
            new->next = tmp;
        }
    }
}

void add_student(char name[], char adress[]) {
    student *p=(student*)malloc(sizeof(student));
    strcpy(p->name,name);
    strcpy(p->adress,adress);
    p->next=NULL;

    if (etudiant==NULL){
        etudiant=p;
    }
    else {
        struct student *q = etudiant;

        while(q->next!=NULL){
            q=q->next;
        }
        q->next=p;
    }
    addModule(p->name, "algo", 15);
}

 int main() {
    add_student("A", "XYZ");
    addModule("A", "CS", 1);
    addModule("A", "MECH", 1);

    add_student("B", "PQR");
    addModule("B", "DAA", 1);
    addModule("b", "SE", 1);

    //printing the list...
    student *q = etudiant;
    while(q != NULL) {
        module *p = q->head;
        printf("%s -> ", q->name);
        while(p != NULL) {
            printf("%s ", p->name);
            p = p->next;
        }
        printf("\n");
        q = q->next;
    }
 }

edited Nov 15, 2016 at 21:31

answered Nov 15, 2016 at 20:08

Rajeev Singh

3,3322 gold badges23 silver badges30 bronze badges

Sign up to request clarification or add additional context in comments.

10 Comments

Mouttie Dje Over a year ago

what if i want to add student's modules at the creating of that student

Rajeev Singh Over a year ago

create the student and just add the modules as in the above function. You don't have to traverse student list in this case coz you already know where to add modules :p

Mouttie Dje Over a year ago

one more question, module pointer is a local one or a global one ? do I need to pass a pointer to module or student in the main function ? :p

Rajeev Singh Over a year ago

it should be local coz you don't need it outside the function in the above implementation. Only one global pointer is needed which will point to the start of the student list, here it is etudiant.

Mouttie Dje Over a year ago

well, i did not really quite understand ur logic, and when i tried it my program crashed, it'd be good if u add some exemple names, thanks

|

Collectives™ on Stack Overflow

linked list inside a linked list (nested linked list)

1 Answer 1

10 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

10 Comments

Your Answer

Sign up or log in

Post as a guest

Related