单链表的修改和删除

单链表建立和单链表的插入完了以后，如果要对链表进行修改和删除，用以下代码：

#include "stdafx.h"
#include
#include
using namespace std;
struct Student{
	string name;
	string score;
	Student *next;//定义了指向Candidate类型变量的指针
};
Student * Create(Student * head){
	Student *p = NULL;
	Student *node = NULL;
	int n;//
	cout << "请输入学生的总数：";
	cin >> n;
	for (int i = 1; i <= n; i++){
		node = new Student;
		cout << "请输入第" << i << "个同学的姓名:";
		cin >> node->name;
		cout << "请输入第" << i << "个同学的成绩:";
		cin >> node->score;
		if (head == NULL)
			head = node;
		else
			p->next = node;
		p = node;
		if (i == n){
			p->next = NULL;
		}
	}
	return head;
}
void Print(Student * head){
	Student *p = NULL;
	p = head;
	cout << "链表已经建立!" << endl;
	cout << "\n==========下面输入刚才的数据=============\n" << endl;
	int i = 1;
	while (p != NULL){
		cout << "第" << i << "个同学===" << p->name << "==成绩====" << p->score << endl;
		p = p->next;
		i++;
	}
	cout << "\n" << endl;
}
void Insert(Student * head, int k){
	Student *p = NULL;
	Student *node = NULL;
	p = head;
	if (k == 1){
		node = new Student;
		cout << "第1位同学的名字：";
		cin >> node->name;
		cout << "第1位同学的成绩：";
		cin >> node->score;
		node->next = head->next;
		head = node;
	}
	int i = 1;
	while (p != NULL){
		if (i + 1 == k){
			node = new Student;
			cout << "第" << k << "位同学的名字：";
			cin >> node->name;
			cout << "第" << k << "位同学的成绩：";
			cin >> node->score;
			node->next = p->next;
			p->next = node;
		}
		p = p->next;
		i++;
	}
}

void Destory(Student * head){
	Student *d;
	Student *p = NULL;
	p = head;
	while (p != NULL){
		d = p;
		p = p->next;
		delete d;
	}
}
void Alter(Student * head, int k){
	int i = 1;
	Student *p = head;
	while (p != NULL){
		if (i == k){
			cout << "第" << k << "位同学的名字：";
			cin >> p->name;
			cout << "第" << k << "位同学的成绩：";
			cin >> p->score;
		}
		p = p->next;
		i++;
	}
}
Student * Delete(Student * head, int k){
	int i = 1;
	Student *p = head;
	Student *d = head;
	if (k == 1){
		head = head->next;
	}
	else{
		while (p != NULL){
			if (i + 1 == k){
				p->next = p->next->next;
			}
			p = p->next;
			i++;
		}
	}
	return head;
}
int main(){
	Student *head = NULL;
	//创建链表
	head = Create(head);
	//输出链表
	Print(head);
	//插入数据
	int k;
	cout << "请输入你要插入的同学的序号：";
	cin >> k;
	Insert(head, k);
	//输出链表
	Print(head);
	//修改链表
	cout << "请输入你要修改的同学的序号:";
	cin >> k;
	Alter(head, k);
	//输出链表
	Print(head);
	//删除其中的一个项
	cout << "请输入你要删除的同学的序号:";
	cin >> k;
	head = Delete(head, k);
	//输出链表
	Print(head);
	//销毁链表
	Destory(head);
	return 0;
}