【求助】c++文件读取
程序代码：#define _CRT_SECURE_NO_WARNINGS//vs中调用strcpy等函数时会提示警告，是因为函数不安全造成内存泄漏
#include<iostream>
using namespace std;
#include<string.h>
#include<fstream>
class student
{
private:
student* next;
public:
char stu_num[15]; //学号
char stu_name[30]; //姓名
float stu_score; //成绩
void afterInsert(student *p);//在该节点后插入一个节点
void afterDelete();//在该节点后删除一个节点
student *getNext()//获得下一个节点的指针
{
return next;
}
/***********查询学生信息************/
void getMage();
/******学生信息修改******/
void changeMage(int n, char *ptr);
void changegrade(float p);
/******构造*****/
student(char *num, char *name, float score);
student();
};
void student::changegrade(float p)
{
stu_score = p;
}
student::student() //构造
{
strcpy(stu_num, "\0");
strcpy(stu_name, "\0");
stu_score = 0;
next = '\0';
}
student::student(char *num, char *name, float score)
{
strcpy(stu_num, num);
strcpy(stu_name, name);
stu_score = score;
next = '\0';
}
void student::afterInsert(student *p)//插入节点
{
p->next = next;
next = p;
}
void student::afterDelete() //删除节点
{
student *p = next;
next = p->next;
delete p;
}
void student::getMage() //获得信息
{
cout << "学号：" << stu_num << " 姓名：" << stu_name;
cout << " c++成绩：" << stu_score << endl;
}
void student::changeMage(int n, char *ptr)
{
switch (n)
{
case 1: strcpy(stu_num, ptr);
break;
case 2: strcpy(stu_name, ptr);
}
}
//建立链表函数
void construct_list(student *tail)
{
student *p = new student;
char very[20];
float achieve;
cout << "请输入学号:" << endl;
cin >> very;
p->changeMage(1, very);
cout << "请输入姓名：" << endl;
cin >> very;
p->changeMage(2, very);
cout << "请输入c++成绩：" << endl;
cin >> achieve;
p->changegrade(achieve);
system("cls");
cout << "信息输入完毕" << endl;
for (; tail->getNext() != '\0';)
{
tail = tail->getNext();
}
tail->afterInsert(p);
}
/*********查询信息*********/
student *findmege(student *head)
{
loop:
cout << "1--按姓名查询 2--按学号查询 q--返回上一级菜单" << endl;
char p[5], ptr[20];
student *mid = head;
cin >> p;
if (p[0] != '1'&&p[0] != '2'&&p[0] != 'q' || strlen(p)>1)
{
system("cls");
cout << "对不起，你的输入有误，请重新输入！" << endl;
goto loop;
}
switch (p[0])
{
case '1':
{
system("cls");
cout << "请输入要查找的姓名：" << endl;
cin >> ptr;
for (; strcmp(ptr, mid->stu_name) != 0; mid = mid->getNext())//strcmp 两值相等 返回0
{
if (mid->getNext() == '\0')
{
cout << "对不起，你要查找的人不存在，请确认你的输入是否正确！" << endl;
goto loop;
}
}
return mid;
}
case '2':
{
system("cls");
cout << "请输入您要查找的学号：" << endl;
cin >> ptr;
for (; strcmp(ptr, mid->stu_num) != 0; mid = mid->getNext())
{
if (mid->getNext() == '\0')
{
cout << "对不起，您要查找的内容不存在，请确认您的输入是否正确！" << endl;
goto loop;
}
}
return mid;
}
case 'q':
{
return '\0';
}
default:
{
system("cls");
cout << "对不起，您的输入有误，请重新输入！" << endl;
goto loop;
}
}
}
/******************删除链表 节点***********************/
void delete_list(student *head)
{
student *p = '\0';
char selet[4];
system("cls");
cout << "在删除前，系统会根据您的提示找到您要删除的学生信息！" << endl;
p = findmege(head);
if (p != '\0')
{
cout << "确认要删除吗（yes/任意键返回）" << endl;
cin >> selet;
if (strcmp(selet, "yes") == 0)
{
for (; head->getNext() != p; head = head->getNext());
head->afterDelete();
system("cls");
cout << "该信息删除成功！" << endl;
}
}
}
/*******************修改节点信息********************/
void change_info(student *head)
{
system("cls");
cout << "在您修改前，系统会根据您提供的信息找的您要修改的信息：" << endl;
student *p = '\0';
float achieve;
p = findmege(head);
if (p != '\0')
{
cout << "请输入c++成绩:" << endl;
cin >> achieve;
p->changegrade(achieve);
system("cls");
cout << "修改成功!" << endl;
}
}
/**************输出学生成绩信息**************/
void output(student *head)
{
system("cls");
cout << "1-查看指定学生信息；2-查看所有学生信息；3-分段输出学生信息" << endl;
char ch;
int n = 0;
head = head->getNext();
cin >> ch;
switch (ch)
{
case '1':
head = findmege(head);
if (head == '\0')
{
break;
}
head->getMage();
break;
case '2':
while (head)
{
head->getMage();
head = head->getNext();
}
break;
case '3':
cout << "a-60分以下；b-60~70分之间；c-70~80分之间；d-80~90分之间；e-90~100分之间：" << endl;
cin >> ch;
switch (ch)
{
case 'a':
while (head)
{
if (head->stu_score <= 60)
{
head->getMage();
n++;
}
head = head->getNext();
}
break;
case 'b':
while (head)
{
if (head->stu_score>60 && head->stu_score <= 70)
{
head->getMage();
n++;
}
head = head->getNext();
}
break;
case 'c':
while (head)
{
if (head->stu_score>70 && head->stu_score <= 80)
{
head->getMage();
n++;
}
head = head->getNext();
}
break;
case 'd':
while (head)
{
if (head->stu_score>80 && head->stu_score <= 90)
{
head->getMage();
n++;
}
head = head->getNext();
}
break;
case 'e':
while (head)
{
if (head->stu_score>90 && head->stu_score <= 100)
{
head->getMage();
n++;
}
head = head->getNext();
}
}
if (n == 0)
{
cout << "该分段内没有您要找的学生信息" << endl;
}
}
}
/*****************主菜单************************/
void mainmenu(student *head)
{
char selet[10];
int n = 1;
ofstream outfile;
student *p, *ptr;
student *test = head, *mid;
cout << "*************************欢迎进入学生信息管理系统*************************" << endl;
do {
cout << "**************************************************************************" << endl;
cout << "1.插入信息； 2.删除信息； 3.修改信息； 4.查看信息； 5.保存 6.读取" << endl;
cout << "按'q'键退出 " << endl;
cout << "**************************************************************************" << endl;
cin >> selet;
if (((selet[0]<'1' || selet[0]>'7') && selet[0] != 'q') || strlen(selet)>1)
{
system("cls");
cout << "您的输入有误，请重新输入！" << endl;
break;
}
switch (selet[0])
{
case '1':
construct_list(head);
break;
case '2':
delete_list(head);
break;
case '3':
change_info(head);
break;
case '4':
output(head);
break;
case '5':
outfile.open("students.txt", ios::out | ios::app);
for (p = head->getNext(); p != '\0'; p = p->getNext())
{
outfile << p->stu_name << ' ';
outfile << p->stu_num << ' ';
outfile << p->stu_score << ' ';
outfile << endl;
}
outfile.close();
system("cls");
cout << "保存成功！" << endl;
break;
case'6':
ifstream infile("student.txt");
for (p = head->getNext(); p != '\0'; p = p->getNext())
{
infile >> p->stu_name;
cout << p->stu_name ;
infile >> p->stu_num ;
cout << p->stu_num ;
infile >> p->stu_score;
cout << p->stu_score;
//infile >> endl;
}; break;
case'q':
break;
}
} while (selet[0] != 'q');
}
void main()
{
student head;
mainmenu(&head);
}
