void reg_student(slist *students, clist *courses, int id, int number){
	slist * temps=NULL,*temps2=NULL;
	clist * tempc=NULL,* tempc2=NULL;
	int in=1;
	for (;students->info->id!=id;students=students->next);
	for (;courses->info->number!=number;courses=courses->next);

	if (!(students->info->courses)){
		if(!(tempc=(clist*)malloc(sizeof(clist)))) exit(1);
		tempc->info=courses->info;
		tempc->next=NULL;
		students->info->courses=tempc;
	}
	else{
		tempc=students->info->courses;
		if (tempc->info->number>number){
			if (!(tempc2=(clist*)malloc(sizeof(clist)))) exit(1);
			tempc2->info=courses->info;
			tempc2->next=tempc;
			students->info->courses=tempc2;
			in=0;
		}
		while (in){
			if (tempc->next && tempc->next->info->number>number){
				if (!(tempc2=(clist*)malloc(sizeof(clist)))) exit(1);
				tempc2->next=tempc->next;
				tempc2->info=courses->info;
				tempc->next=tempc2;
				break;
			}
			if (!(tempc->next)){
				if (!(tempc2=(clist*)malloc(sizeof(clist)))) exit(1);
				tempc2->info=courses->info;
				tempc2->next=NULL;
				tempc->next=tempc2;
				break;
			}
			tempc=tempc->next;
		}
	}
	if (!(courses->info->students)){
		if(!(temps=(slist*)malloc(sizeof(slist)))) exit(1);
		temps->info=students->info;
		temps->next=NULL;
		courses->info->students=temps;
	}
	else{
		temps=courses->info->students;
		if (temps->info->id>id){
			if (!(temps2=(slist*)malloc(sizeof(slist)))) exit(1);
			temps2->info=students->info;
			temps2->next=temps;
			courses->info->students=temps2;
			return ;
		}
		while (1){
			if (temps->next && temps->next->info->id>id){
				if (!(temps2=(slist*)malloc(sizeof(slist)))) exit(1);
				temps2->next=temps->next;
				temps2->info=students->info;
				temps->next=temps2;
				return;
			}
			if (!(temps->next)){
				if (!(temps2=(slist*)malloc(sizeof(slist)))) exit(1);
				temps2->info=students->info;
				temps2->next=NULL;
				temps->next=temps2;
				return;
			}
			temps=temps->next;
		}
	}
}
void unreg_student(slist *students, int id, int number){
	clist * tempc;
	slist * temps;

	for (;students->info->id!=id;students=students->next);
	tempc=students->info->courses;
	for (;tempc->info->number!=number;tempc=tempc->next);
	temps=tempc->info->students;
	for (;temps->info->id!=id;temps=temps->next);
	tempc->info->students= remove_from_list_s(tempc->info->students,temps);
	students->info->courses= remove_from_list_c(students->info->courses,tempc);
}