Lỗi Stopped working trong C

Anh, chị ai giúp xem code của em lỗi chỗ nào mà khi chạy nó bị lỗi .exe have stopped work.
Code em đây ạ:

#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h>
// Dinh nghia struct de luu thong tin sinh vien
typedef struct
{
	char name[40];
	char account[15];
	char subject[15];
	int score;
}STUDENT, *PSTUDENT;
//khai bao danh sach lien ket don
struct Node
{
	STUDENT n;
	Node *pNext;
};

struct SLL
{
	Node *pHead;
	Node *pTail;
};
//khoi tao danh sach lien ket don
void initSLL(SLL &list)
{
	list.pHead = list.pTail = NULL;
}
//In danh sach ra man hinh
void output (STUDENT x)
{
    printf("
%s		%s		%s		%d",x.name,x.account,x.subject,x.score);
}
void viewSLL (SLL list)
{
    Node *pNode;
    pNode=list.pHead;
    while(pNode!=NULL)
    {
        output(pNode->n);
        pNode=pNode->pNext;
    }
}
//Tao 1 nut moi
Node *newNode(STUDENT k)
{
	Node *pNode;
	pNode = (Node*)malloc(1 * sizeof(Node));
	//if (!pNode)
	//{
	//	return NULL;
	//}
	pNode->n = k;
	pNode->pNext = NULL;
	return pNode;
}
//Chen 1 nut vao cuoi danh sach
void AddLast (SLL &list, Node *pNode)
{
    //if(list.pHead==NULL)  
	//	list.pHead=list.pTail=pNode;
    //else
    //{
        list.pTail->pNext=pNode;
        list.pTail=pNode;
    //}
}
//Nhap
void input (STUDENT k)
{
    printf("
Nhap ten sinh vien: ");  fflush(stdin); gets(k.name);
    printf("
Nhap account: ");  fflush(stdin); gets(k.account);   
    printf("
Nhap mon hoc: "); fflush(stdin); gets(k.subject);
    printf("
Nhap diem: "); scanf("%d",&k.score);
}
//Search
void Search (SLL list)
{
	STUDENT m;
    Node *pNode;
    int dem=0;
    char a[15];
    printf("
Nhap account sv can tim: ");
    fflush(stdin);
    gets(a);
    pNode=list.pHead;
    while (pNode!=NULL)
    {
        if(strcmp(a,pNode->n.account)==0)      dem++;
        pNode=pNode->pNext;
    }
    if(dem!=0)
    {
    	m=pNode->n;
        printf("
Tim thay sv: ");
		printf("
%s	%s	%s	%d",m.name,m.account,m.subject,m.score);
    }
    else
	    printf("
Ko tim thay.");
}
//Delete
void Delete (SLL &list)
{
    Node *pNode, *qNode;
    char a[15];
    pNode=list.pHead;
    qNode=NULL;
    printf("
Nhap account can xoa: ");
    fflush(stdin);
    gets(a);
    while (pNode!=NULL)
    {
        if(strcmp(a, pNode->n.account)==0)    break;
        else printf("
Ko co sv can xoa.");
        qNode=pNode;
        pNode=pNode->pNext;
    }
    if(qNode!=NULL)
    {
        if(pNode!=NULL)
        {
            qNode->pNext=pNode->pNext;
            delete (pNode);
            if(pNode==list.pTail)
				list.pTail=qNode;
            delete(pNode);
        }
    }
    else
    {
        list.pHead=pNode->pNext;
        delete(pNode);
        if(list.pHead==NULL)  list.pTail=NULL;
    }
}
int main()
{
	SLL list;
	Node *pNode;
	STUDENT k;
	int a;
	initSLL(list);
	do
	{
		printf("*************************************************
");
		printf("*		STUDENT MANAGEMENT		*
");
		printf("*************************************************
");
		printf("1.Insert student
");
		printf("2.Delete student
");
		printf("3.Search student base on account
");
		printf("4.Show student imformation
");
		printf("5.Save student imformation to STUDENT.LOG file
");
		printf("6.EXIT

");
		printf("Which option would you like?
");
		scanf("%d",&a);
		switch(a)
		{
			case 1:
				{
					STUDENT chen;
					printf("Nhap thong tin sinh vien can insert:
");
					input(chen);
					Node *t = newNode(chen);
					AddLast(list,t);
					printf("Danh sach sau khi them: 
");
					viewSLL(list);
					break;
				}
			case 2:
				{
					Delete(list);
					printf("Danh sach sau khi xoa: 
");
					viewSLL(list);
					break;
				}
			case 3:
				{
					Search(list);
					break;
				}
			case 4:
				{
					printf("Danh sach sinh vien: 
");
					viewSLL(list);
					break;
				}
			default:printf("Nhap lai:
");		
		}
	} while(a!=6);
	getch();
}