数据结构实验2——链表

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <windows.h>
#include <cwchar>
#include <string>

using namespace std;

#define ok 1
#define error 0
#define overflow -2

const int maxn = 1e5 + 10;
struct student{
    char id[80];
    char name[80];
    double grade;
}e, ss;

typedef struct lnode{
    student data;
    struct lnode *next;
    int length;
}lnode, *linklist;

linklist l, s;
string head1, head2, head3;
int length;

//初始化链表
int initlist(linklist &ll){
    ll = new lnode;
    ll->next = nullptr;
    ll->length = 0;
    return ok;
}

//前插法构建链表
int createlist_before(linklist &ll, int n){
   ll = new lnode;
   l->next = nullptr;
   for(int j = 0; j < n; j ++ ){
       auto r = new lnode;
       cin>>r->data.id>>r->data.name>>r->data.grade;
       r->next = ll->next;
       ll->next = r;
       ll->length ++ ;
   }
   return ok;
}

//获取
int getelem(linklist ll, int i){
    auto p = ll->next;
    int j = 1;
    while(p && j < i){
        p = p->next;
        j ++ ;
    }
    if(!p->next || j > i) return error;
    ss = p->data;
    return ok;
}

//后插法创建单链表
int createlist_after(linklist &ll, int n){
    ll = new lnode;
    ll->next = nullptr;
    auto r = ll;
    for(int j = 0; j < n; j ++ ){
        auto u = new lnode;
        cin>>r->data.id>>r->data.name>>r->data.grade;
        u->next = nullptr;
        r->next = u;
        r = u;
        ll->length ++ ;
    }
    return ok;
}

//显示链表内容
int listdisplay(linklist ll){
    auto p = ll;
    int len = p->length;
    for(int j = 0; j < len; j ++ ){
        p = p->next;
        cout<<"学号："<<p->data.id<<endl;
        cout<<"姓名："<<p->data.name<<endl;
        cout<<"成绩："<<p->data.grade<<endl<<endl;
    }
    return ok;
}

//单链表的按值查找
lnode *locatelem(linklist ll, char ee[]){
    auto p = ll->next;
    while(p && strcmp(p->data.name, ee) != 0)
        p = p->next;
    return p;
}

//单链表的插入
int listinsert(linklist &ll, int i, student ee){
    auto p = ll;
    int j = 1;
    while(p->next && j < (i - 1)){
        p = p->next;
        j ++ ;
    }
    if(!p->next || j > (i - 1)) return error;
    s = new lnode;
    s->data = ee;
    s->next = p->next;
    p->next = s;
    ll->length ++ ;
    return ok;
}

//单链表的删除
int listdelete(linklist &ll, int i){
    auto p = ll;
    int j = 1;
    while(p->next && j < (i - 1)){
        p = p->next;
        j ++ ;
    }
    if(!p->next || j > (i - 1)) return error;
    lnode *pp = p->next;
    p->next = pp->next;
    delete pp;
    ll->length -- ;
    return ok;
}

//销毁链表
int distroylist (linklist &ll){
    int len = ll->length;
    for(int j = 1; j <= len; j ++ ){
        listdelete(ll, j);
    }
    auto pp = ll->next;
    ll->next = nullptr;
    delete pp;
    ll->length -- ;
    return ok;
}

int main()
{
    SetConsoleOutputCP(65001);
    int choose;
    char name[80];
    char num[80];

    cout<<"---------------"<<endl;
    cout<<"1.初始化链表"<<endl;
    cout<<"2.前插法构建链表"<<endl;
    cout<<"3.后插法构建链表"<<endl;
    cout<<"4.求链表长度"<<endl;
    cout<<"5.显示链表内容"<<endl;
    cout<<"6.查找学生信息"<<endl;
    cout<<"7.获取学生信息"<<endl;
    cout<<"8.插入学生信息"<<endl;
    cout<<"9.删除学生信息"<<endl;
    cout<<"10.销毁链表"<<endl;
    cout<<"0.退出"<<endl<<endl;
    cout<<"---------------"<<endl;

    choose = -1;
    while(choose != 0){
        cout<<"请选择:";
        cin>>choose;
        switch(choose){
            case 1:{
                if(initlist(l)) cout<<"成功建立单链表！"<<endl<<endl;
                break;
            }
            case 2:{
                cout<<"请输入要插入的个数："<<endl;
                int x, y;
                cin>>x;
                cout<<"请输入学生的学号，姓名，成绩（空格隔开）"<<endl;
                int a = createlist_before(l, x);
                if(a) cout<<"输入student.txt 信息完毕"<<endl<<endl;
                break;
            }
            case 3:{
                cout<<"请输入要插入的个数："<<endl;
                int x, y;
                cin>>x;
                cout<<"请输入学生的学号，姓名，成绩（空格隔开）"<<endl;
                int a = createlist_after(l, x);
                if(a) cout<<"输入student.txt 信息完毕"<<endl<<endl;
                break;
            }
            case 4:{
                cout<<"长度为:"<<l->length<<endl<<endl;
                break;
            }
            case 5:{
                int a = listdisplay(l);
                cout<<"显示完毕"<<endl<<endl;
                break;
            }
            case 6:{
                cout<<"请输入一个位置用来取值：";
                int i;
                cin>>i;
                if(getelem(l, i)){
                    cout<<"查找成功
";
                    cout<<"学号："<<ss.id<<endl;
                    cout<<"姓名："<<ss.name<<endl;
                    cout<<"成绩："<<ss.grade<<endl<<endl;
                }
                else cout<<"查找失败"<<endl<<endl;
                break;
            }
            case 7:{
                cout<<"请输入所要查找学生姓名:";
                cin>>name;
                auto p = locatelem(l, name);
                if(p != nullptr){
                    cout<<"查找成功"<<endl;
                    cout<<"对应的学生信息为："<<endl;
                    cout<<"学号："<<p->data.id<<endl;
                    cout<<"姓名："<<p->data.name<<endl;
                    cout<<"成绩："<<p->data.grade<<endl<<endl;
                }
                else cout<<"查无此人"<<endl<<endl;
                break;
            }
            case 8:{
                cout<<"请输入插入的位置和学生的学号姓名成绩（用空格隔开）："<<endl;
                int i;
               // char str[2];
                cin>>i;
                //scanf("%c", &str);
                cin>>e.id>>e.name>>e.grade;
                if(listinsert(l, i, e))
                    cout<<"插入成功"<<endl<<endl;
                else cout<<"插入失败"<<endl<<endl;
                break;
            }
            case 9:{
                cout<<"请输入要删除的学生的编号：";
                int i;
                cin>>i;
                if(listdelete(l, i)) cout<<"删除成功"<<endl<<endl;
                else cout<<"删除失败"<<endl<<endl;
                break;
            }
            case 10:{
                if(distroylist(l)) cout<<"成功销毁链表！"<<endl<<endl;
                break;
            }
        }
    }
    return 0;
}

总结：写下一个实验注意变量的定义（自己都不记得用过没有了）