建立某链表的有关问题

Question

‎建立一个链表，链表节点用于存储如下结构体：

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‎ struct Student

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‎ { long num; //学号

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‎ char name[20]; //姓名

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‎ char sex; //性别

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‎ float score; //成绩

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‎ };

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‎要求：使用函数和指针进行合理的编程，

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‎ 建立链表

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struct SLink

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{ struct Student s;

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struct SLink *next;

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} *np;

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‎ ，并设计如下函数：

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‎ 1）createLink()生成一个空链表；

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‎ 2）insertData(struct Student s)按学生学号由小到大的顺序，将s插入到链表合适的位置；

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‎ 提示：使用np=(struct SLink *) malloc(sizeof(struct SLink)开辟内存以建立新节点。

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‎ 3）deleteData(long num)删除学号为num的节点。

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‎ 提示：使用free(np)释放被删除节点的内存;

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‎ 4）printLink()顺序打印输出链表各节点的内容。

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Answer 1

#include<iostream>
using namespace std;

struct Student
{
    long num; //学号
    char name[20]; //姓名
    char sex; //性别
    float score; //成绩
};

struct SLink
{
    struct Student s;
    struct SLink* next;
} *np;

void createLink()
{
    np = nullptr;
}

void insertData(struct Student s) 
{
    if (np == nullptr){
        np = (struct SLink*)malloc(sizeof(struct SLink));
        np->s = s;
        np->next = nullptr;
        return;
    }
    SLink* pPrevNode = nullptr;
    SLink* pNode = np;
    while (pNode) {
        if (s.num <= pNode->s.num) {
            if (pPrevNode == nullptr) {
                np = (struct SLink*)malloc(sizeof(struct SLink));
                np->s = s;
                np->next = pNode;
            }
            else {
                pPrevNode->next = (struct SLink*)malloc(sizeof(struct SLink));
                pPrevNode->next->s = s;
                pPrevNode->next->next = pNode;
            }
            break;
        }
        if (pNode->next == nullptr){
            pNode->next = (struct SLink*)malloc(sizeof(struct SLink));
            pNode->next->s = s;
            pNode->next->next = nullptr;
            break;
        }
        pPrevNode = pNode;
        pNode = pNode->next;
    }
}

void deleteData(long num)
{
    SLink* pPrevNode = nullptr;
    SLink* pNode = np;
    while (pNode){
        if (num == pNode->s.num){
            if (pPrevNode == nullptr){
                np = pNode->next;
            }
            else{
                pPrevNode->next = pNode->next;
            }
            //SLink* pNext = pNode->next;
            free(pNode);
            break;
           // pNode = pNext;
        }
        else{
            pPrevNode = pNode;
            pNode = pNode->next;
        }
    }
}

void printStudent(const Student& stud)
{
    cout << stud.num << "\t" << stud.name << "\t" << (stud.sex ? "male" : "female") << "\t" << stud.score << endl;
}

void printLink() 
{
    cout << "num\t" << "name\t" << "sex\t" << "score" << endl;
    SLink* pNode = np;
    while (pNode) {
        printStudent(pNode->s);
        pNode = pNode->next;
    }
}

int main(void)
{
    createLink();

    struct Student a {0, "a", true,  100};
    struct Student b {10, "b", true,  90};
    struct Student c {2, "c", true,  80};
    struct Student d {3, "d", true,  100};
    struct Student e {43, "e", true,  99};
    struct Student f {5, "f", true,  60};

    insertData(a);
    insertData(b);
    insertData(c);
    insertData(d);
    insertData(e);
    insertData(f);

    printLink();
    deleteData(10);
    printLink();

    int i;
    cin >> i;

    return 0;
}