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

struct course {
    char CN [20];
    double avg;
    struct student *sh;
    struct course *next;
};

struct student {
    char SN[20];
    int age;
    int ID;
    double score[4];
    struct student *next;
};



struct student* CreateStudentList (){  // יצירת רשימה מקושרת של סטודנטים
    struct student *p, *head=NULL, *tail;
    int i;

    while(1){
        printf("Any key to add student, esc to finish: \n");
        flushall();
        if (getch() == 27) break;

        p= (struct student *)malloc (sizeof(struct student));
        printf("  Enter student name: ");
        gets (p->SN);
        printf("  Enter student age: ");
        scanf("%d",&p->age);
        printf("  Enter student ID: ");
        scanf("%d",&p->ID);
        for(i=0;i<4;i++){
            printf("  %d  Enter score: ",i+1);
            scanf("%lf",&p->score[i]);
        }


        if (head ==NULL){
            head = tail = p;
            p->next = NULL;
        }
        else {
            tail -> next = p;
            p-> next = NULL;
            tail = p;
        }

    }
    return head;
}

///

struct course* CreateCourseList (){  //  רשימה מקושרת של קורסים שמקשרים אל רשימות סטודנטים
    struct course *p, *head=NULL, *tail;
    struct student *q;
    int i,h;
    double avg=0.0;

    while(1){
        printf("Press esc to exit, any key to continue and create a new course: \n");
        flushall();
        if (getch() == 27) break;

        p = (struct course *)malloc (sizeof(struct course));
        printf("Enter course name: ");
        gets (p->CN);
        p-> sh = CreateStudentList ();
        if (!p->sh) return NULL; // ==      if (p-> sh==NULL) return NULL;


        p->avg = 0.0;
        for(q=p->sh,h=0; q ;q=q->next,avg=0.0,h++){

        for(i=0;i<4;i++)
        avg += (q->score[i]);

        avg = avg/4.0;
        p->avg +=avg;
    }
        p->avg = (p->avg)/h;

        printf("There is: %d students in %s course \n",h,p->CN);
        printf("The avg score of all the students in the %s course is: %.3lf \n\n\n",p->CN,p->avg);

        if (head == NULL){
            head = tail = p;
            p->next = NULL;
        }
        else {
            tail -> next = p;
            p-> next = NULL;
            tail = p;
        }

    }
    return head;
}







void main(){
    struct course *p;
    p = CreateCourseList ();

}