链表基本功能实现c++实现

#include <iostream>
#include <string>
using namespace std;

struct Student
{
    string name;
    int score;
    Student* next;
};
Student* head = NULL;
void addNode(string n, int s);
void printNodeInfo(Student* temp);
void releaseNode(Student* temp);
double average(Student* temp);
void sortNodeByScore(Student* temp);
void deleteNodeByName(Student* temp, string n);

int main()
{
    addNode("zhangsan", 40);
    addNode("lisi", 90);
    addNode("wangwu", 80);
    addNode("sunliu", 70);
    addNode("qiangqi", 50);
    printNodeInfo(head);
    //double result = average(head);
    //cout << "result: " << result << endl;
    //sortNodeByScore(head);
    //cout << "after sort\n";
    //printNodeInfo(head);

    cout << "delete node by name\n";
    deleteNodeByName(head,"sunliu");
    printNodeInfo(head);
    deleteNodeByName(head,"xiaowangzi");

    releaseNode(head);
    system("pause");
    return 0;
}
void addNode(string n, int s)
{
    //创建临时节点
    Student* temp = NULL;
    Student* stu = new Student;
    stu->name = n;
    stu->score = s;
    if (head == NULL)
    {
        head = stu;
        head->next = NULL;
        cout << "添加节点成功\n";
    }
    else
    {
        temp = head;
        while (temp->next != NULL)
        {
            temp = temp->next;
        }
        temp->next = stu;
        stu->next = NULL;
        cout << "添加节点成功\n";
    }
}
void printNodeInfo(Student* temp)
{
    if (temp == NULL)
    {
        cout << "链表为空\n";
    }
    else
    {
        while (temp != NULL)
        {
            cout << "name: " << temp->name << " score: " << temp->score << endl;
            temp = temp->next;
        }
    }
}
void releaseNode(Student* temp)
{
    Student* newP = NULL;
    if (temp == NULL)
    {
        cout << "链表节点内存为空\n";
    }
    else
    {
        while (temp != NULL)
        {
            newP = temp;
            temp = temp->next;
            delete newP;
            cout << "节点内存清除成功\n";
        }
    }
}
//遍历 求成绩平均值
double average(Student* temp)
{
    double average;
    double sum = 0;
    int count = 0;
    if (temp == NULL)
    {
        cout << "链表为空\n";
        //处理除数为0的情况
        return 0;
    }
    else
    {
        while (temp != NULL)
        {
            sum += temp->score;
            count++;
            temp = temp->next;
        }
    }
    return sum / count;

}
//void sortNodeByScore(Student* temp)
//{
//    //创建一个临时节点
//    Student* newP = NULL;
//    //创建内层循环节点
//    Student* newPIn = NULL;
//    if (temp == NULL)
//    {
//        cout << "链表为空，不需要排序\n";
//    }
//    else
//    {
//        //创建双重循环来实现按score排序
//        newP = temp;
//        while (newP->next != NULL)
//        {
//            newPIn = newP;
//            while (newPIn->next != NULL)
//            {
//                if (newP->score > newPIn->next->score)
//                {
//                    //交换节点的score值
//                    int tempValue;
//                    tempValue = newP->score;
//                    newP->score = newPIn->next->score;
//                    newPIn->next->score = tempValue;
//                }
//                newPIn = newPIn->next;
//            }
//            newP = newP->next;
//        }
//        //如果只有一个节点 代码没问题
//    }
//}
//代码优化 创建一个临时节点即可
void sortNodeByScore(Student* temp)
{
    //创建内层循环节点
    Student* newPIn = NULL;
    if (temp == NULL)
    {
        cout << "链表为空，不需要节点\n";
    }
    else
    {
        //创建双重循环按score排序
        while (temp->next != NULL)
        {
            newPIn = temp;
            while (newPIn->next != NULL)
            {
                if (temp->score > newPIn->next->score)
                {
                    int tempValue;
                    tempValue = temp->score;
                    temp->score = newPIn->next->score;
                    newPIn->next->score = tempValue;
                }
                newPIn = newPIn->next;
            }
            temp = temp->next;
        }
    }
}
void deleteNodeByName(Student* temp, string n)
{
    //创建一个临时节点 用来保存要删除节点的前一个节点
    Student* newP = NULL;
    //创建一个节点 用来保存要删除的节点
    Student* newPDelete = NULL;
    if (temp == NULL)
    {
        cout << "链表为空，没有可以删除的节点\n";
    }
    else
    {
        newP = temp;
        //如果只有一个节点 头节点
        if (newP->next == NULL)
        {
            if (newP->name.compare(n) == 0)
            {
                delete newP;
                return;
            }
        }
        while (newP->next != NULL)
        {
            if (newP->next->name.compare(n) == 0)
            {
                newPDelete = newP->next;
                //这句代码还要好好考虑
                //如果newPDelete->next为null 代码没问题么
                newP->next = newPDelete->next;
                delete newPDelete;
                //方法结束
                return;
            }
            newP = newP->next;
        }
        //链表节点中没有该name
        cout << "the link nodes don't have you input name " << n << endl;
    }
}