学生管理程序

这是一个简单的学生管理程序，记录了四个不同版本

1.第一次学生管理程序(结构体实现):

#define _CRT_SECURE_NO_WARNINGS 1//防止scanf报错
#include<stdio.h>
#include<string.h>
typedef struct STUDENTS {//主结构体
    int number;
	char name[100];
	int sex;
	union stu {//联合体
		struct student {
		unsigned int year:11;
		unsigned int month:4;
		unsigned int day:5;
		}birthday;
		int date;
	}STU;
	int score[4];
}STUDENT;
enum types {//枚举类型
	男 = 0,
	女 =1
};

void Input(STUDENT student[],int n);//输入函数
void Search(char name[], STUDENT student[], int n);//查找函数
void Average(STUDENT student[],int n);//平均成绩和及格率函数
void Comparemin(STUDENT student[], int n);//最小年龄显示函数
int compare(char names[], STUDENT student[100], int n);//匹配字符串的函数
void trans1(STUDENT student[], int n);//联合体中两成员的值互化，下同
void trans2(STUDENT student[], int n);
int main()
{
	STUDENT student[100];
	int n, chose,func;
	char names[100];
	part1:printf("请先输入班级学生信息,输入1跳转: ");
	scanf("%d", &chose);
	rewind(stdin);
	if (chose == 1) {
		printf("请输入班级人数:");
		scanf("%d", &n);
		Input(student, n);
	}
	else if (chose != 1) {
		printf("输入错误!,请重新输入\n");
		goto part1;
	}
	printf("请选择你要使用的功能:\n");
	printf("1.查找学生信息\n");
	printf("2.统计某科目的平均成绩和及格率\n");
	printf("3.查找年龄最小的学生信息\n");
	scanf("%d", &func);
	switch (func)
	{	
	case 1:
		printf("请输入学生姓名 ");
		rewind(stdin);
		gets(names);
		Search(names, student, n);
		break;
	case 2:
		Average(student, n);
		break;
	case 3:
		Comparemin(student, n);
		break;
	}
	return 0;
}
void Input(STUDENT student[100], int n) {//输入函数
	int i,j;
	printf("请依次输入学号:");
	for (i = 0; i < n; i++)
	scanf("%d",&student[i].number);
	printf("请依次输入学生姓名:");
	for (i = 0; i < n; i++)
	scanf("%s", student[i].name);
	printf("请依次输入学生的性别(男:0女:1):");
	for (i = 0; i < n; i++)
	scanf("%d", &student[i].sex);
	printf("请依次输入学生出生年: 月: 日:\n");
	for (i = 0; i < n; i++) {
		int year, month, day;
		scanf("%d%d%d", &year, &month, &day);
		student[i].STU.birthday.year = year;
		student[i].STU.birthday.month =month;
		student[i].STU.birthday.day = day;
	}
	printf("请依次输入学生的语文 数学 英语 理综成绩:\n");
	for (i = 0; i < n; i++) {
		for (j = 0; j < 4; j++) {
			scanf("%d", &student[i].score[j]);
		}
	}
}
void Search(char names[], STUDENT student[], int n)//查找函数
{
	int a;
	a = compare(names, student, n);
	if (a!=-1){
		printf("您输入的学生信息如下:\n");
		printf("姓名: %s\n", student[a].name);
		printf("学号: %d\n", student[a].number);
		if (student[a].sex == 0)
			printf("性别: 男\n");
		else if (student[a].sex == 1)
			printf("性别: 女\n");
		printf("出生日期: %d%02d%02d\n", student[a].STU.birthday.year, student[a].STU.birthday.month, student[a].STU.birthday.day);
		printf("该学生的各科成绩为\n语文:%d\n", student[a].score[0]);
		printf("数学:%d\n", student[a].score[1]);
		printf("英语:%d\n", student[a].score[2]);
		printf("理综:%d\n", student[a].score[3]);
	}
		else if(compare(names, student, n)==-1)
			printf("无该学生信息\n");
	}
int compare(char names[] ,STUDENT student[], int n) {//名字匹配
	int i,flag,j;
	for (i = 0; i < n; i++)
	{
		for (j = 0; j < strlen(names); j++) {
			if (names[j] == student[i].name[j]) 
				flag = 1;
			else {
				flag = 0;
				break;
			}
		}
		if (flag == 1)
			return i;
	}
	if (flag == 0)
		return -1;
}
void Average(STUDENT student[], int n)//及格率和平均成绩
{
	int subject,i;
	double avg,pass,sum=0;
	int a=0, b=0;
	printf("请输入你想统计的科目:\n1.语文\n2.数学\n3.英语\n4.理综\n");
		scanf("%d",&subject);
		if (subject == 1){
			for (i = 0; i < n; i++){
				sum += student[i].score[0];}
			for (i = 0; i < n;i++)
			{if (student[i].score[0] >= 60)
					a++;
				else if (student[i].score[0] < 60)
					b++;}
			avg = sum / n;
			pass = (double)a / (a + b);
			printf("语文的平均成绩为:%.2lf\n语文的及格率为%%%.2lf", avg, pass);}
		else if (subject == 2) {
			for (i = 0; i < n; i++) {
				sum += student[i].score[1];}
			for (i = 0; i < n; i++){
				if (student[i].score[1] >= 60)
					a++;
				else if (student[i].score[1] < 60)
					b++;}
			avg = sum / n;
			pass = (double)a / (a + b);
			printf("数学的平均成绩为:%.2lf\n数学的及格率为%%%.2lf", avg, pass);}
		else if (subject == 3) {
			for (i = 0; i < n; i++) {
				sum += student[i].score[2];}
			for (i = 0; i < n; i++){
				if (student[i].score[2] >= 60)
					a++;
				else if (student[i].score[2] < 60)
					b++;}
			avg = sum / n;
			pass = (double)a / (a + b);
			printf("英语的平均成绩为:%.2lf\n英语的及格率为%%%.2lf", avg, pass);}
		else if (subject == 4) {
			for (i = 0; i < n; i++) {
				sum += student[i].score[3];}
			for (i = 0; i < n; i++){
				if (student[i].score[3] >= 60)
					a++;
				else if (student[i].score[3] < 60)
					b++;}
			avg = sum / n;
			pass = (double)a / (a + b);
			printf("理综的平均成绩为:%.2lf\n理综的及格率为%%%.2lf", avg, pass);}
}
void Comparemin(STUDENT student[], int n)
{
	trans1(student, n);
	int min=0,i;
	for (i =0; i < n;i++)//找出年龄最小的学生对应的出生日期
	{
		if (min < student[i].STU.date)
			min = student[i].STU.date;
			
	}

	for (i = 0; i < n; i++)
	{
		if (min == student[i].STU.date)//学生匹配
		{
			break;
		}
	}
	trans2(student, n);
	printf("年龄最小的学生信息如下:\n");
	printf("姓名: %s\n", student[i].name);
	printf("学号: %d\n", student[i].number);
	if (student[i].sex == 0)
		printf("性别: 男\n");
	else if (student[i].sex == 1)
		printf("性别: 女\n");
	printf("出生日期: %d%02d%02d\n", student[i].STU.birthday.year, student[i].STU.birthday.month, student[i].STU.birthday.day);
	printf("该学生的各科成绩为\n语文:%d\n", student[i].score[0]);
	printf("数学:%d\n", student[i].score[1]);
	printf("英语:%d\n", student[i].score[2]);
	printf("理综:%d\n", student[i].score[3]);
}

void trans1(STUDENT student[], int n)//联合体中两成员值的转换
{
	int i;
	for (i = 0; i < n; i++)
	{
		student[i].STU.date = (student[i].STU.birthday.year)* 10000 + (student[i].STU.birthday.month) * 100 + student[i].STU.birthday.day;
	}
}
void trans2(STUDENT student[], int n)//联合体中两成员值的转换
{
	int i,a;
	for (i = 0; i < n; i++)
	{
		a = student[i].STU.date;
		student[i].STU.birthday.year = a / 10000;
		student[i].STU.birthday.month = (a%10000)/100;
		student[i].STU.birthday.day = a % 100;
	}
}

2.第二次学生管理程序(链表实现)

main.c

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include"function.h"

int main()
{
    FILE* p;
    p = fopen("student", "r");
    if (p == NULL)
    {
        printf("加载数据失败,开始录入学生数据:\n");
        Input();
    }
    else
    {
        fclose(p);
        read();
    }
    menu();
}

function.c

#define _CRT_SECURE_NO_WARNINGS 1//防止scanf报错
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
struct STUDENT {//主结构体
    int number;
    char name[50];
    int sex;
    union stu {//联合体
        struct birthday {
            unsigned int day : 5;
            unsigned int month : 4;
            unsigned int year : 11;
        }stus;
        int date;
    }STU;
    int score[4];
    struct STUDENT* next;
};
struct STUDENT* head = NULL;
struct STUDENT* student = NULL, * current = NULL;//创建链表结点

enum types {
    男 = 0,
    女 = 1
};
void Input() {
    int i;
    char temp[50];
    while (1)
    {
        current = (struct STUDENT*)malloc(sizeof(struct STUDENT));
        if (current != NULL) {
            if (head == NULL)
                head = current;
            else
                student->next = current;
            current->next = NULL;
            puts("请输入学生姓名: ");
            gets(temp);
            strcpy(current->name, temp);
            puts("请输入该学生的学号: ");
            scanf("%d", &current->number);
            puts("请输入该学生的性别(男:0女:1): ");
            scanf("%d", &current->sex);
            puts("请输入学生的出生日期年 月 日: ");
            int year, month, day;
            scanf("%d %d %d", &year, &month, &day);
            current->STU.stus.year = year;
            current->STU.stus.month = month;
            current->STU.stus.day = day;
            puts("请依次输入学生的语文 数学 英语 理综成绩: ");
            scanf("%d %d %d %d", &current->score[0], &current->score[1], &current->score[2], &current->score[3]);
            student = current;
            rewind(stdin);
            printf("继续输入请按1,输入完成请按2:");
            scanf("%d", &i);
            getchar();
            if (i == 1)
                continue;
            else
                break;
        }
    }
}
void Find() {

    puts("所有学生的信息如下:\n");
    current = head;
    while (current != NULL)
    {
        printf("学生姓名:%s\n", current->name);
        printf("学号:%d\n", current->number);
        if (current->sex == 0)
            printf("性别: 男\n");
        else if (current->sex == 1)
            printf("性别: 女\n");
        printf("出生日期:%d%02d%02d\n", current->STU.stus.year, current->STU.stus.month, current->STU.stus.day);
        printf("该学生的各科成绩为\n语文:%d\n", current->score[0]);
        printf("数学:%d\n", current->score[1]);
        printf("英语:%d\n", current->score[2]);
        printf("理综:%d\n", current->score[3]);
        current = current->next;
    }
}
void Search() {
    char names[50];
    printf("请输入学生的姓名: ");
    scanf("%s", names);
    current = head;
    while (current != NULL) {
        if (match(names, current) == 1)//匹配名字
        {
            printf("您要查找的学生信息如下:\n");
            printf("姓名: %s\n", current->name);
            printf("学号: %d\n", current->number);
            if (current->sex == 0) {
                printf("性别: 男\n");
            }
            else if (current->sex == 1)
            {
                printf("性别: 女\n");
            }
            printf("出生日期:%4d%02d%02d\n", current->STU.stus.year, current->STU.stus.month, current->STU.stus.day);
            printf("该学生的各科成绩为\n语文:%d\n", current->score[0]);
            printf("数学:%d\n", current->score[1]);
            printf("英语:%d\n", current->score[2]);
            printf("理综:%d\n", current->score[3]);
            break;
        }
        current = current->next;
    }
    if (current == NULL)
        printf("没有该学生信息\n");
}


void Average()
{
    int subject, n = 0;//n用于统计结点个数
    double avg = 0, sum = 0;
    current = head;
    printf("请输入你想统计的科目:\n1.语文\n2.数学\n3.英语\n4.理综\n");
    scanf("%d", &subject);
    if (subject == 1) {
        while (current != NULL)
        {
            sum += current->score[0];
            current = current->next;
            n++;
        }
        avg = sum / n;
        printf("语文的平均成绩为:%.2lf", avg);
    }
    else if (subject == 2) {
        while (current != NULL)
        {
            sum += current->score[2];
            current = current->next;
            n++;
        }
        avg = sum / n;
        printf("数学的平均成绩为:%.2lf", avg);
    }
    else if (subject == 3) {
        while (current != NULL)
        {
            sum += current->score[2];
            current = current->next;
            n++;
        }
        avg = sum / n;
        printf("英语的平均成绩为:%.2lf\n", avg);
    }
    else if (subject == 4) {
        while (current != NULL)
        {
            sum += current->score[3];
            current = current->next;
            n++;
        }
        avg = sum / n;
        printf("理综的平均成绩为:%.2lf", avg);
    }
}

int match(char names[], struct STUDENT* current)
{
    int flag, i;
    for (i = 0; i < strlen(names); i++)
    {
        if (current->name[i] == names[i])
        {
            flag = 1;
        }
        else if (current->name[i] != names[i])
        {
            flag = 0;
            break;
        }
    }
    if (flag == 1)
        return 1;
    else  if (flag == 0)
        return 0;
}
void preserve()
{
    current = head;
    FILE* p1;
    p1 = fopen("student", "w");
    if (p1 == NULL)
    {
        printf("文件打开失败");
        exit(1);
    }
    while (current != NULL)
    {
        fprintf(p1, "%s\n", current->name);
        fprintf(p1, "%d\n", current->number);
        fprintf(p1, "%d\n", current->sex);
        fprintf(p1, "%4d%02d%02d\n", current->STU.stus.year, current->STU.stus.month, current->STU.stus.day);
        fprintf(p1, "%d\n", current->score[0]);
        fprintf(p1, "%d\n", current->score[1]);
        fprintf(p1, "%d\n", current->score[2]);
        fprintf(p1, "%d\n", current->score[3]);
        current = current->next;
    }

    if (fclose(p1) != 0)
        printf("文件关闭失败");
    else
        printf("保存数据成功,文件关闭成功\n");
}
void read()
{
    FILE* p2;
    p2 = fopen("student", "r");
    if (p2 == NULL) {
        printf("打开文件失败");
        exit(1);
    }
    while (!feof(p2))//读取到文件结尾
    {
        current = (struct STUDENT*)malloc(sizeof(struct STUDENT));
        if (head == NULL)
            head = current;
        else
            student->next = current;
        current->next = NULL;
        fscanf(p2, "%s\n", current->name);
        fscanf(p2, "%d\n", &current->number);
        fscanf(p2, "%d\n", &current->sex);
        int year, month, day;
        fscanf(p2, "%4d%02d%02d\n", &year, &month, &day);。
        current->STU.stus.year = year;
        current->STU.stus.month = month;
        current->STU.stus.day = day;//设置位宽后的处理
        fscanf(p2, "%d\n", &current->score[0]);
        fscanf(p2, "%d\n", &current->score[1]);
        fscanf(p2, "%d\n", &current->score[2]);
        fscanf(p2, "%d\n", &current->score[3]);
        student = current;

    }
    if (fclose(p2) != 0)
        printf("文件关闭失败");
    else
        printf("学生数据加载成功\n");
}
void SearchID() {
    int a, b = 0;
    printf("请输入学生的学号: ");
    scanf("%d", &a);
    current = head;
    while (current != NULL)
    {
        if (a == current->number)
        {
            break;
        }
        current = current->next;
        b++;
    }
    if (current == NULL)//到达最后一个结点的判断条件
        printf("无该学生信息");
    else {
        printf("该学生信息如下:\n");
        printf("姓名: %s\n", current->name);
        printf("学号: %d\n", current->number);
        if (current->sex == 0) {
            printf("性别: 男\n");
        }
        else if (current->sex == 1)
        {
            printf("性别: 女\n");
        }
        printf("出生日期:%4d%02d%02d\n", current->STU.stus.year, current->STU.stus.month, current->STU.stus.day);
        printf("该学生的各科成绩为\n语文:%d\n", current->score[0]);
        printf("数学:%d\n", current->score[1]);
        printf("英语:%d\n", current->score[2]);
        printf("理综:%d\n", current->score[3]);
    }
}
void DeleteID()
{
    int a, flag;
    printf("请输入删除学生的学号: ");
    scanf("%d", &a);
    current = head;
    while (current->next != NULL)
    {
        if (current->next->next != NULL) {
            if (current->next->number == a)
            {
                current->next = current->next->next;
                flag = 1;//删除改链表结点
                break;
            }
        }
        else//删除链表尾结点
        {
            if (current->next->number == a) {
                current->next = NULL;
                flag = 1;
                break;
            }
        }
        current = current->next;
        flag = 0;
    }
    if (flag == 1)
        printf("删除成功");
    else
        printf("删除失败,找不到该学生");

}
void Deletename()
{
    char names[50];
    int flag;
    printf("请输入删除学生的姓名: ");
    scanf("%s", names);
    current = head;
    while (current->next != NULL)
    {
        if (current->next->next != NULL) {
            if (match(names, current) == 1)
            {
                current->next = current->next->next;//删除列表结点
                flag = 0;
                break;
            }
        }
        else
        {
            if (match(names, current->next) == 1) {//单独处理列表尾结点
                current->next = NULL;
                flag = 0;
                break;
            }
        }
        flag = 1;
        current = current->next;
    }
    if (flag == 0)
        printf("删除成功");
    else {
        printf("删除失败,没有该学生信息");
    }
}
void menu()
{
    int func;
    printf("请选择你要使用的功能:\n");
    printf("1.查看所有学生\n");
    printf("2.姓名查找学生信息\n");
    printf("3.学号查找学生信息\n");
    printf("4.输入学号删除学生信息\n");
    printf("5.输入姓名删除学生信息\n");
    printf("6.统计某科目的平均成绩\n");
    printf("7.保存学生数据\n");
    scanf("%d", &func);
    switch (func)
    {
    case 1:
        Find();
        break;
    case 2:
        rewind(stdin);
        Search();
        break;
    case 3:
        SearchID();
        break;
    case 4:
        DeleteID();
        break;
    case 5:
        Deletename();
        break;
    case 6:
        Average();
        break;
    case 7:
        preserve();
        break;
    }
}

3.第三次学生管理程序(类+链表+c++ 实现)

define.h:

#include<iostream>
#include<string>
class Student {
	private:
            int number;
            std::string name;
            int sex;
            union stu {//联合体
                struct birthday {
                    unsigned int day : 5;
                    unsigned int month : 4;
                    unsigned int year : 12;
                }stus;
                int date;
            }STU;
            int score[4];
            
    public:
        Student()//构造函数初始化变量
        {
            number = 0;
            name = "names";
            sex = 0;
            score[0] = { 0 };
            score[1] = { 0 };
            score[2] = { 0 };
            score[3] = { 0 };
        }
        Student* next = nullptr;
        friend class Classroom;//友元类(使得current能够访问Student类中的私有变量)
};
class Classroom
{
    private:
        Student* head = nullptr;      //指向下一结点
        Student* latter = nullptr;
        Student* current = nullptr;       //c++中用nullptr代表空指针,而NULL当作0使用
    public: 
        void Input();
        void Find();
        void Search();
        void SearchID();
        void Average();
        void DeleteID();
        void Deletename();
        void preserve();
        void read();
        void menu();
};

achieve.cpp:

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<fstream>//用于处理文件输入输出
#include<cstdlib>//为exit()提供原型
#include"define.h"
using namespace std;
void Classroom::Input() {
    int i;
    while (1)
    {
       current = new Student; 
        if (head == nullptr)
            head = current;
        else
            latter->next = current;
            current->next = nullptr;
            cout << "请输入学生姓名: ";
            cin >>current->name;
            cout <<"请输入该学生的学号: ";
            cin >> current->number;
            cout<<"请输入该学生的性别(男:0女:1): ";
            cin >> current->sex;
            cout<<"请输入学生的出生日期年 月 日: ";
            rewind(stdin);
            int year, month, day;
            cin >> year ;
            cin >> month;
            cin >> day;
            current->STU.stus.year = year;
            current->STU.stus.month = month;
            current->STU.stus.day = day;
            cout<<"请依次输入学生的语文 数学 英语 理综成绩: ";
            cin >> current->score[0] >> current->score[1] >> current->score[2] >>current-> score[3];
            latter = current ;
            cout << "继续输入请按1,输入完成请按2:";
            cin >> i;
            if (i == 1)
                continue;
            else
                break;
        }
    }
void Classroom::Find()
{
    puts("所有学生的信息如下:\n");
    current = head;
    while (current != nullptr)
    {
        cout << "学生姓名: " << current->name << endl;
        cout << "学号: " << current->number << endl;
        cout << "性别: " << current->sex << endl;
        if (current->sex == 0)
            cout << "性别: 男" << endl;
        else if (current->sex == 1)
            cout << "性别: 女" << endl;
        cout << "出生日期: " << current->STU.stus.year <<" "<< current->STU.stus.month <<" "<< current->STU.stus.day << endl;
        cout << "该学生的各科成绩为: " << endl;
        cout << "语文: " << current->score[0] << endl;
        cout << "数学: " << current->score[1] << endl;
        cout << "英语: " << current->score[2] << endl;
        cout << "理综: " << current->score[3] << endl;
        current = current->next;
    }
}
void Classroom::Search() {
     string names;
     cout<<"请输入学生的姓名: ";
     cin >> names;
    current = head;
    while (current != nullptr) {
        if (names==current->name)//匹配名字
        {
            cout<<"您要查找的学生信息如下: "<<endl;
            cout<<"姓名: "<<current->name<<endl;
            cout<<"学号: "<< current->number<<endl;
            if (current->sex == 0)
                cout << "性别: 男" << endl;
            else if (current->sex == 1)
                cout << "性别: 女" << endl;
            cout << "出生日期: " << current->STU.stus.year << " " << current->STU.stus.month << " " << current->STU.stus.day << endl;
            cout << "该学生的各科成绩为: " << endl;
            cout << "语文: " << current->score[0] << endl;
            cout << "数学: " << current->score[1] << endl;
            cout << "英语: " << current->score[2] << endl;
            cout << "理综: " << current->score[3] << endl;
            break;
        }
        current = current->next;
    }
    if (current == nullptr)
        cout<<"没有该学生信息\n";
}
void Classroom::SearchID() {
    int a, b = 0;
    cout << "请输入学生的学号: ";
    cin >> a;
    current = head;
    while (current != nullptr)
    {
        if (a == current->number)
        {
            break;
        }
        current = current->next;
        b++;
    }
    if (current == nullptr)//到达最后一个结点的判断条件
        cout << "无该学生信息";
    else {
        cout << "您要查找的学生信息如下: " << endl;
        cout << "姓名: " << current->name << endl;
        cout << "学号: " << current->number << endl;
        if (current->sex == 0)
            cout << "性别: 男" << endl;
        else if (current->sex == 1)
            cout << "性别: 女" << endl;
        cout << "出生日期: " << current->STU.stus.year << " " << current->STU.stus.month << " " << current->STU.stus.day << endl;
        cout << "该学生的各科成绩为: " << endl;
        cout << "语文: " << current->score[0] << endl;
        cout << "数学: " << current->score[1] << endl;
        cout << "英语: " << current->score[2] << endl;
        cout << "理综: " << current->score[3] << endl;
    }
}
 void Classroom::Average()
    {
        int subject, n = 0;//n用于统计结点个数
        double avg = 0, sum = 0;
        current = head;
        cout<<"请输入你想统计的科目:\n1.语文\n2.数学\n3.英语\n4.理综\n";
        cin >> subject;
        if (subject == 1) {
            while (current != nullptr)
            {
                sum += current->score[0];
                current = current->next;
                n++;
            }
            avg = sum / n;
            cout<<"语文的平均成绩为: "<< avg;
        }
        else if (subject == 2) {
            while (current != nullptr)
            {
                sum += current->score[2];
                current = current->next;
                n++;
            }
            avg = sum / n;
            cout<<"数学的平均成绩为: "<< avg;
        }
        else if (subject == 3) {
            while (current != nullptr)
            {
                sum += current->score[2];
                current = current->next;
                n++;
            }
            avg = sum / n;
            cout << "英语的平均成绩为: " << avg;
        }
        else if (subject == 4) {
            while (current != nullptr)
            {
                sum += current->score[3];
                current = current->next;
                n++;
            }
            avg = sum / n;
            cout << "理综的平均成绩为: " << avg;
        }
    }
 
 void Classroom::DeleteID()
 {
     int a, flag;
        cout<<"请输入删除学生的学号: ";
        cin >> a;
        current = head;
     while (current->next != nullptr)
     {
         if (current->number == a)//删除列表头结点
         {
             head = current->next;
             delete(current);
             flag = 1;
             break;
         }
         if (current->next->next != nullptr) {
             if (current->next->number == a)
             {
                 current->next = current->next->next;
                 delete(current->next);
                 flag = 1;//删除改链表结点
                 break;
             }
         }
         else//删除链表尾结点
         {
             if (current->next->number == a) {
                 current->next = nullptr;
                 delete(current->next);
                 flag = 1;
                 break;
             }
         }
         current = current->next;
         flag = 0;

     }
     if (flag == 1)
         cout<<"删除成功";
     else
         cout <<"删除失败,找不到该学生";
 }
 void Classroom::Deletename()
 {
     string names;
     int flag;
     cout<<"请输入删除学生的姓名: ";
     cin >> names;
     current = head;
     while (current->next != nullptr)
     {
 
             if (current->name == names)//删除列表头结点
             {
                 head = current->next;
                 delete(current);
                 flag = 0;
                 break;
             }
          if (current->next->next != nullptr) {
              if (names==current->next->name)
             {
                  delete(current->next);
                 current->next = current->next->next;//删除列表结点
                 flag = 0;
                 break;
             }
         }
         else
         {
             if (names == current->next->name) {//单独处理列表尾结点
                 delete(current->next);
                 current->next = nullptr;
                 flag = 0;
                 break;
             }
         }
         flag = 1;
         current = current->next;
     }
     if (flag == 0)
        cout << "删除成功";
     else {
        cout << "删除失败,没有该学生信息";
     }
 }
 void Classroom::preserve()
 {
     current = head;
     ofstream outFile;
     outFile.open("student.txt");
     if (!outFile.is_open()) {//判断文件是否打开成功，打开成功返回true
         cout << "文件打开失败";
             exit(1);
     }
     while (current != nullptr)
     {
        outFile<<current->name<<endl;
        outFile<< current->number << endl;
        outFile << current->sex << endl;
        outFile << current->STU.stus.year << endl << current->STU.stus.month << endl << current->STU.stus.day << endl;
        outFile << current->score[0] << endl;
        outFile << current->score[1] << endl;
        outFile << current->score[2] << endl;
        outFile << current->score[3] << endl;
         current = current->next;
         
     }
     outFile.close();
     cout << "保存成功";
 }
 void Classroom::read()
 {
     ifstream inFile;
     inFile.open("student.txt");
     if (!inFile.is_open())
     {
         cout << "文件打开失败";
         exit(1);
     }
     while (!inFile.eof())//读取到文件结尾
     {
         current = new Student;
         if (head ==nullptr)
             head = current;
         else
             latter->next = current;
         current->next = nullptr;
         inFile >> current->name;
         inFile >> current->number;
         inFile >> current->sex;
         int year, month, day;
         inFile >> year;
         inFile >> month;
         inFile >> day;
         current->STU.stus.year = year;
         current->STU.stus.month = month;
         current->STU.stus.day = day;//设置位宽后的处理
         inFile >> current->score[0];
         inFile >> current->score[1];
         inFile >> current->score[2];
         inFile >> current->score[3];
         latter = current;

     }
     inFile.close();
     cout << "学生数据加载成功\n";
 }

main.cpp:

#include<iostream>
#include<fstream>
#include"define.h"
Classroom a;//创建Classroom对象(变量)，便于调用函数,同时创建的全局变量，具有外部链接，便于菜单调用;
int main()
{
    std::ifstream inFile;
    inFile.open("student.txt", std::ios::in);//第一个参数为文件名，第二个参数为打开方式，ios::in为只读模式
    if (!inFile.is_open())
    {
        std::cout << "开始录入数据:";
        a.Input();
    }
    else {
        inFile.close();
        a.read();
        std::cout << "数据加载成功" << std::endl;
    }
    a.menu();
}

menu.cpp:

#include<iostream>
#include"define.h"
void Classroom::menu()
{
    int func;
    extern Classroom a;//extern引用声明main文件中的a
    printf("                 **********请选择你要使用的功能: **********                  \n");
    printf("                 **********1.查看所有学生       **********                 \n");
    printf("                 **********2.姓名查找学生信息   **********                  \n");
    printf("                 **********3.学号查找学生信息    **********                  \n");
    printf("                 **********4.输入学号删除学生信息**********                  \n");
    printf("                 **********5.输入姓名删除学生信息**********                  \n");
    printf("                 **********6.统计某科目的平均成绩**********                  \n");
    printf("                 **********7.保存学生数据        **********                  \n");
    std::cin >> func;
    switch (func)
    {
    case 1:
        a.Find();
        break;
    case 2:
        rewind(stdin);
        a.Search();
        break;
    case 3:
        a.SearchID();
        break;
    case 4:
        a.DeleteID();
        break;
    case 5:
        a.Deletename();
        break;
    case 6:
        a.Average();
        break;
    case 7:
        a.preserve();
        break;
    }
}

4.第四个版本在github仓库

5.Base64编码解码

bitset——定义及常用操作

bitset 就相当于一个 只能存储二进制，也就是 0 和 1 的 bool 数组(容器)
但是可以直接当作一个数进行左移右移，取或取反等二进制操作。

如果直接用 bool 数组存储二进制每一位的话，n 位存储复杂度为 O(n)，但是用 bitset 的话复杂度会减少到 O(n/32)。

所以一般用二进制状态压缩时就会用 bitset。

使用时引入头文件#include

定义：

对于 bitset 的定义有四种方式：
1、直接定义，每一位初始为0：
bitset<N> name; // 定义长度为 N 的二进制数组，命名为 name；

bitset<8> b1;
cout << b1 <<endl; // 00000000

2、存储数字的二进制：
bitset<N> name(num); // 定义长度为 N 的二进制数组，命名为 name，将数字 num 的二进制存到其中；

bitset<8> b2(12); //二进制长度8，将12转化为二进制存到其中。
cout << b2 << endl;

3、存储 01字符串 对应的二进制：
bitset<N> name(string); // 定义长度为 N 的二进制数组，命名为 name，将01串 string 存到其中，长度不够前补 0，长度过长截断；

string s = "10010";
bitset<8> b3(s);
cout << b3 << endl;

4、存储 01字符数组 中的二进制：
bitset<N> name(char[]); // 定义长度为 N 的二进制数组，命名为 name，将 01字符数组存到其中，长度不够前补0，长度过长截断；

char chs[10] = "10010";
bitset<8> b4(chs);
cout << b4 << endl;

注意：
直接输出 bitset 为正常的二进制，但是遍历所有位置来输出的话就是逆序的：

bitset<8> bs(13);
cout << bs <<endl; //00001101
for(int i=0;i<7;i++) cout<<bs[i]; //10110000

常用操作：

像数字一样进行 取或 或者 左移右移：

b2 |= b3; //两个二进制数取或操作； 
b2 &= b3; //两个二进制数取与操作； 
b2 ^= b3; //取异或；
b2 = ~b2; //取反; 
b2 <<= 2; //左移右移；自带函数：

自带函数：

int cnt_1 = b2.count(); //查询二进制数组中，1的个数；
int len  = b2.size(); //二进制数组的长度，就是定义的长度； 
int test = b2.test(7); //判断第x个位置是0还是1，也就是输出第x个位置，注意逆序；

b2.flip(); //将二进制每一位取反；
b2.flip(3); //将二进制第x位取反；
b2.set(); //将二进制每一位置为1； reset置为0； 
b2.set(3); //将第x个位置置为1；
	

常用操作:

string ss = b2.to_string(); //将二进制数组转化为字符串.

代码实现:

main.c

#include<iostream>
#include"main.h"
using namespace std;

int main() {
    DATA data,data1;
    int choose;
    cout<<"选择你想使用的功能(请确保进行操作的文件路径存在):"<<endl;
    cout<<"*****1.   编码   *****"<<endl;
    cout<<"*****2.   解码   *****"<<endl;
    cout<<"*****3.创建编码文件*****"<<endl;
    cout<<"*****4.创建解码文件*****"<<endl;
    cin >> choose;
    switch(choose)
    {
        case 1:
            inFile(data);
            transform_2_string(data);
            encode_number(data);
            transform_string_10(data);
            output_encode(data);
            outFile_encode(data);
            break;
        case 2:
            inFile(data1);
            decode_2_string(data1);
            decode_number(data1);
            decode_string_10(data1);
            output_decode(data1);
            outFile_decode(data1);
            break;
        case 3:
            Input_encode(data);
        case 4:
            Input_decode(data1);
    }
    return 0;
}

main.h

///
// Created by 柯秋迪 on 2022/11/29.
//

#ifndef UNTITLED2_MAIN_H
#define UNTITLED2_MAIN_H
#include<string>
using namespace std;
struct DATA {
    const char aci[64]={'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V',
                        'W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r',
                        's','t','u','v','w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/'};//映射表
    string input;
    string trans_input;
    string a[100];
    int b[100];
};
void transform_2_string(DATA &data);
void encode_number(DATA &data);
void transform_string_10(DATA &data);
void output_encode(DATA &data);
void decode_2_string(DATA &data1);
void decode_number(DATA &data1);
void decode_string_10(DATA &data1);
void output_decode(DATA &data1);
void inFile(DATA &data);
void outFile_decode(DATA &data1);
void outFile_encode(DATA &data);
void Input_encode(DATA &data);
void Input_decode(DATA &data1);
#endif //UNTITLED2_MAIN_H

define.c

//
// Created by 柯秋迪 on 2022/11/29.
//
#include<iostream>
#include<string>
#include<bitset>
#include<cmath>
#include<fstream>
#include<cstring>
#include"main.h"
unsigned int num;
void transform_2_string(DATA &data){
    for(int i=0;i<data.input.size();i++) {
        bitset<8>bs(data.input[i]);//将数据转化为二进制储存在bs中
        data.trans_input+=bs.to_string();//将bs中的数据转化为字符串
    }
}
void encode_number(DATA &data)
{
    int j=0;
    if(data.trans_input.size()%24==0) {//每一组完全占满的情况
        num = data.trans_input.size() / 6;
        for (int i = 0; i < num; i++) {
            for (; j < data.trans_input.size(); j++) {
                data.a[i] += data.trans_input[j];
                if (j >= 5) {
                    if ((j + 1) % 6 == 0) {
                        j++;
                        break;
                    }
                }
            }
        }
    }
    else{//不完全占满的情况
        num = (data.trans_input.size() / 24);
        if(num==0)
            num=4;
        else
            num=4*((data.trans_input.size()/24)+1);
        for(int i=0;i<num;i++)
        {
            for(;j<data.trans_input.size();j++)
            {
                data.a[i]+=data.trans_input[j];
                if(j>=5)
                {
                    if((j+1)%6==0)
                    {
                        j++;
                        break;
                    }
                }

            }


        }
    }
    for (int i = 0; i < num; i++) {
        if (data.a[i].size() < 6) {
            size_t n = data.a[i].size();//size()的返回值为size_t/unsigned int类型,用int型接收返回值会警告,返回值为正数
            if (!data.a[i].empty()) {
                for (int k = 0; k < 6 - n; k++) {
                    data.a[i].push_back('0');//不能用0,0是数值无法加到字符串后面，0不是字符'0'才是，'0'可加到后面
                }
            } else
                for (int m = 0; m < 6; m++)
                {
                    data.a[i].push_back('0');
                }
        }
    }
}
void transform_string_10(DATA &data){

    for(int i=0;i<num;i++)
    {
        if(data.a[i]!="000000") {
            int l = 0;
            double sum=0;
            for ( int j = data.a[i].size() - 1; j >= 0; j--) {
                sum += (data.a[i][l] - 48) * pow(2, j);//
                l++;// 字符数字转数值
            }
            data.b[i] = (int)sum;
        }
        else
            data.b[i]=64;//对等号的单独处理
    }
}
void output_encode(DATA& data) {
    cout<<"编码后为:";
    for (int i = 0; i < num; i++) {
        int j=0;
        for (; j < 64; j++) {
            if (data.b[i] == j) {
                cout << data.aci[j];
                break;
            }
        }
        if(j==64)//与上方令其为64呼应
            cout<<'=';
    }
    cout<<endl;
}





void decode_2_string(DATA &data1) {

    for(int n=0;n<data1.input.size();n++) {
        for (int m = 0; m < 64; m++) {
                if (data1.input[n] == data1.aci[m]) {
                    data1.input[n]=(char)m;
                    break;
                }  //先将需要解码的字符变为base64中匹配的aci码
        }
    }

    for (int i = 0; i < data1.input.size(); i++) {
        if(data1.input[i]!='='){
        bitset<6> bs(data1.input[i]);
        data1.trans_input += bs.to_string();
        }


}
}
void decode_number(DATA &data1) {
    int j = 0;
    if (data1.trans_input.size() % 8 == 0) {
        num = data1.trans_input.size() / 8;
    } else {
        num = (data1.trans_input.size() / 8) + 1;
    }
    for (int i = 0; i < num; i++) {
        for (; j < data1.trans_input.size(); j++) {
            data1.a[i] += data1.trans_input[j];
            if (j >= 7) {
                if ((j + 1) % 8 == 0) {
                    j++;
                    break;
                }
            }
        }
    }
    for (int i = 0; i < num; i++) {
        if (data1.a[i].size() < 8) {
            size_t k = 8 - data1.a[i].size();//补齐8位
            for (int m = 0; m < k; m++)
                data1.a[i].push_back('0');//注意不要写成0了，0为数值不能添加到字符串后面，应为'0'是字符才能放到字符串的后面
        }
    }
}
void decode_string_10(DATA &data1){
    for(int i=0;i<num;i++) {

        if (data1.a[i] != "000000") {//为=时就会全为0，当全为0时不会转换
            for (int j = 0; j < 8; j++) {
                int l = 0;
                double sum = 0;
                for (int k = data1.a[i].size() - 1; k >= 0; k--, l++) {
                    sum += (data1.a[i][l] - 48) * pow(2, k);// 字符数字转数值
                }
                data1.b[i] = (int) sum;
            }
        }
        else
            data1.b[i]=64;//对等号的处理防止出现奇怪的字符
    }
    }
void output_decode(DATA &data1)
{
    cout<<"解码后为:";
    for(int i=0;i<num;i++)
    {
        if(data1.b[i]!=64)
        printf("%c",data1.b[i]);
    }
    cout<<endl;
}


void inFile(DATA &data){
    string encode_txt;
    cout <<"请输入文件路径:";
    cin >> encode_txt;
    ifstream inFile;
    inFile.open(encode_txt,ios::in);//只读模式打开
    if(!inFile.is_open())
    {
        cout << "找不到需要编码的文件,程序已自动结束";
        exit(1);
    }
    inFile >> data.input;
    inFile.close();
}

void outFile_decode(DATA &data1)
{
    string encode_txt;
    cout <<"请输入保存结果的文件路径:";
    cin >> encode_txt;
    ofstream outFile;
    outFile.open(encode_txt);
    if(!outFile.is_open())
    {
    cout << "文件保存失败";
    exit(1);
    }
    for(int i=0;i<num;i++)
    {
        if(data1.b[i]!=64)
            outFile << (char)data1.b[i];
    }
   outFile.close();
    cout << "文件保存成功";
}
void outFile_encode(DATA &data)
{
    string encode_txt;
    cout <<"请输入保存结果的文件路径:";
    cin >> encode_txt;
    ofstream outFile;
    outFile.open(encode_txt);
    if(!outFile.is_open())
    {
        cout << "文件保存失败";
        exit(1);
    }
    for (int i = 0; i < num; i++) {
        int j=0;
        for (; j < 64; j++) {
            if (data.b[i] == j) {
                cout << data.aci[j];
                break;
            }
        }
        if(j==64)//与上方令其为64呼应
            outFile<<'=';
    }
}
void Input_encode(DATA &data) {
    cout<<"请输入编码内容:";
    cin.get();//吸收回车;
    getline(cin,data.input);//此处不用cin，否则会造成有空格的时候，会被截断,下同
    transform_2_string(data);
    encode_number(data);
    transform_string_10(data);
    output_encode(data);
    outFile_encode(data);
}
void  Input_decode(DATA &data1){
    cout<<"请输入解码内容:";
    cin.get();//吸收回车;
    getline(cin,data1.input);
    decode_2_string(data1);
    decode_number(data1);
    decode_string_10(data1);
    output_decode(data1);
    outFile_decode(data1);
}