Добавление Элементов В Двусвязный Список

#include "stdafx.h"
#include <stdlib.h>
#include <stdio.h>

struct school
{
char* name;
char* surname;
char* year;

struct school *next;
struct school *prew;
};

struct school * temp=NULL;
struct school * start=NULL;

void add(char year,char* name, char* surname)
{
struct school *a=(struct school*)malloc(sizeof(struct school));
a->surname=surname;
a->next=temp;
if (start==NULL){
start=a;
}
else
{
temp->prew=a;
}

temp=a;
temp->prew=NULL;

}