c语言：单链表的实现（一） 创建，插入，删除，查找

#include<iostream>
#include<stdio.h>
#include<math.h>
#define NULL 0
#define LEN sizeof(struct Student)
using namespace std;
typedef struct Student
{
	int length;
	int num;
	struct Student *next;
}Student; 
typedef Student *Linklist;    //头指针
void Error(char *s)           //错误指示
{
	std::cout << s << endl;
	exit(1);
}
Student *creat(void)          //创建链表
{
	Student *head;
	Student *p, *q;
    int	n = 0;
	 q = (Student*)malloc(LEN);
	 p = q;
	 cout << "请输入元素:" << endl;
	 cin >> p->num;
	head = NULL;
	while (p->num != 0)
	{
		n = n + 1;
		if (n == 1)
		{
			head = p;
			head->length = 1;
		}
		else
		{
			q->next = p;
			q = p;
			p = (Student*)malloc(LEN);
			cin >> p->num;
			head->length++;
		}
	}
	q->next = NULL;
	return head;
	cout << "链表创建成功！" << endl;
}

void Insertlist(Linklist &L, int i, int stu)
//向链表中第i个位置插入元素stu
{
	Student *p =L;              //将指针头传给指针p   
	int j = 1;
	while (p && (j < i - 1))   //向后扫描查找
	{
		p = p->next;
		j++;
	}
	if (!p || (j < i - 1))     //输入参数不对，给出错误提示，并跳出
		Error("Postion Eeeor!");
	else
	{
		Student *s = new Student;
		s->num =stu;
		s->next = p->next;
		p->next = s;
		p->length++;
	}
}
void Deletelist(Linklist &L, int i, int stu)
//删除链表中第i个元素，并用stu返回
{
	Student *p = L; //将指针头传给指针p 
	int j = 1;
	while (p && (j < i - 1))
	{
		p = p->next;
		j++;
	}
	if (!p || (j < i - 1))
		Error("Postion Eeeor!"); // 输入参数不对，给出错误提示，并跳出
	else
	{
		Student *q = p->next;
		stu= p->num;
		p->next = q->next;
		delete q;
		p->length--;
	}
}
void Traverlist(Linklist L)  //将链表依次数据输出
{
	Student *p = L;
	while (p)
	{
		cout << p->num << " ";
		p = p->next;
	}
	cout << endl;
}

Student *Location(Linklist &L, int stu) //查找函数,查找元素stu所在的位置
{
	int i = 2;
	Student *p = L->next;
	if (i<L->length-1)
	{
		while (p->next != NULL && (p->num != stu))
		{
			p = p->next;
			i++;
		}
		cout << "该元素所在的位置是：" << i << endl;
	}
	else
		cout << "该元素不存在！" << endl;
	return  p;
}
int main()
{
	Student *head, *p;
	int stu,n, number;
	while (1)
	{
		cout << "    1、创建信息表" << endl;
		cout << "    2、插入元素" << endl;
		cout << "    3、查询元素" << endl;
		cout << "    4、删除元素" << endl;
		cout << "    5、退出程序" << endl;
		cout << "    请选择所要执行的操作:";
		cin >> n;
		switch (n)
		{
		case 1:
			head=creat();
			Traverlist(head);

			break;
		case 2:
			cout << "请输入插入的位置和元素:";
			cin >> number;
			cin >> stu;
			while (stu != 0)
			{
				Insertlist(head, number, stu);
				Traverlist(head);
				cout << "请输入插入的位置和元素:";
				cin >> number;
				cin >> stu;
			}
			break;
		case 3:
			cout << "请输入查找的元素:";
			cin >> stu;
			while (stu != 0)
			{
				p = Location(head, stu);
				cout << "请输入查找的元素:";
				cin >> stu;
			}
		   
			break;
		case 4:
			cout << "请输入要删除的位置 :";
			cin >> number;
			while (number!=0)
			{
				Deletelist(head, number, stu);
				Traverlist(head);
				cout << "请输入要删除的位置 :";
				cin >> number;
			}
			break;//程序结束
		case 5:
			exit(1);
			break;//程序结束
		default:
			cout << "输入错误，请重新输入!!!!!" << endl;
			continue;
		}
	}
	return 0;
}