链表删除和显示问题！

[smdszgzh]

#include "Student.h"
#include <iostream>
#include <string>
using namespace std;
typedef struct ListNode
{
	string sID;
	string sName;
	string bSex;
	double Score[2];
	ListNode* pNext;
}Node;

class StudentList
{
	Node* pHead;
	Node* pNew;
	Node* pTail;
public:
	StudentList(){pHead=NULL;};
	Node* ReadStudent(StudentList &list);
	void DeleteStudent();
	void ShowStudent(StudentList &list);
	Node* SelectStudent();
	Node* SearchStudent();
};

void StudentList::ShowStudent(StudentList &list)
{
	cout<<"ID		"<<"Name		"<<"Sex		"<<"English		"<<"Math"<<endl;
	Node* p=pHead;
	while(p!=NULL)
	{
		cout<<p->sID<<"		"<<p->sName<<"		"<<p->bSex<<"		"
			<<p->Score[0]<<"		"<<p->Score[1]<<endl;
		p=p->pNext;
	}
}

void StudentList::DeleteStudent()
{
	string ID;
	cout<<"Please input the student's ID"<<endl;
	cin>>ID;
	Node* pPre;
	Node* p=pHead;
	while(p!=NULL)
	{
		pPre=p;
		if(ID==p->sID)//因为学号唯一，所以查找到后直接删除，不用继续查找
		{
			pPre->pNext=p->pNext;
			delete p;
			cout<<"删除成功！"<<endl;
			return;
		}
		p=p->pNext;
	}
	cout<<"不存在些学号的学生纪录"<<endl;
}

不用删除功能可以正常显示，当用了删除功能后就不能正常显示了，报错！

[猫已经找不回了]

while(p!=NULL)
    {
        pPre=p;
        if(ID==p->sID)//因为学号唯一，所以查找到后直接删除，不用继续查找
        {
            pPre->pNext=p->pNext;         // 这里明显有问题。
            delete p;
            cout<<"删除成功！"<<endl;
            return;
        }
        p=p->pNext;
    }


/****修改后***/
while(p->next!=NULL)             //因为你是单链，删除后，找不到前驱节点。
    {
        pPre=p->next;                //pPre标记要删除的对象
        if(ID==p->next->sID)//唯一，所以查找到后直接删除，不用继续查找
        {
            p->pNext=p->pNext->next;    //要删除pPre，p指向它
            delete pPre;
            cout<<"删除成功！"<<endl;
            return;
        }
        p=p->pNext;
    }

[猫已经找不回了]

不好意思，帮上面代码里的next都改成pNext