这是我第一次在这个网站上发帖，所以请不要错过任何错误/礼仪搞砸了！
基本上我周三有一个项目（是的，一个班级）。代码用C ++编写，它是一个程序，它从下面列出的.txt文件中获取以下数据成员（在学生类中定义）：
class Student
{
public:
//other functions such as add/edit/delete, etc... go here
private:
string firstname;
string lastname;
int grade; //1 for Freshman, 2 for Sophmore, 3 for Junior, 4 for Senior
int student_id;
double credit_hours; //credit hours taken
double GPA; //current GPA
};
我还附上了下面的.txt文件。基本上我必须在.txt文件中读入该类类型的数组，即Student类的对象。我们的老师说我们可以假设阵列的最大尺寸是[100]学生。我尝试过readFile（）函数的几种变体，但都没有。我知道我必须超载＆gt;＆gt;运算符与Student类一起工作，但我不知道如何做到这一点。她建议朋友的功能？
这是名为“StudentRecords.txt”的.txt文件，与另一个.cpp文件保存在同一目录中。
Harry
Smith
2
11121321
100
3.8
Mary
Jones
1
43213843
56
3.1
Nicolas
Dodsworth
4
54219473
120
2.3
J.Alfred
Prufrock
4
83746321
122
4.0
T.S.
Eliot
1
99999999
126
4.0
Charlotte
Webb
3
44443333
98
3.8
Don
Juan
1
12345678
56
1.2
John
Smith
2
54234876
66
2.85
Darth
Vader
2
87623450
49
2.55
3
CPO
4
33333333
100
4.0
Emily
Dickinson
3
23456120
110
3.6
James
Buchanan
1
5640012
30
2.23
Carl
Rove
1
12995425
28
1.6
Marie
Curie
4
88888888
96
3.5
Micky
Mouse
2
8222222
64
1.85
James
Madison
3
66633333
88
2.96
Dolly
Madison
3
53423445
84
3.24
Pepe
LePew
1
73737373
42
2.47
Homer
Simpson
4
7223344
105
1.03
Mary
Jones
1
09274726
28
2.92
Bloss
Sims
4
11111111
100
1.2
谢谢你们！我非常感谢你的帮助。我对C ++主要是Python没有很多经验，所以这肯定会帮助我。
编辑：
以下代码。 read函数是最后一个函数：
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
class stdRecord
{
public:
string studentID;
string studentName;
int courseCode;
int creditPoint;
};
const int MAXRECORD = 100;
int menu();
void searchStudent(stdRecord[],int);
void showByCourse(stdRecord[],int);
//void showEligible(stdRecord[],int);
void showAll(stdRecord[],int);
void update(stdRecord[],int );
void add(stdRecord[],int *);
void deleteRecord(stdRecord[],int *);
void findCourses(stdRecord [],int );
int main()
{
stdRecord stdRec[MAXRECORD]={"15000000","Joshua Andrew Smith", 3506, 240,"16666666", "Jack Williams", 3506, 180,"17000010", "Lily Jones", 3639, 110};
int counter=3;
int choice;
do
{
choice=menu();
switch(choice)
{
case 0: cout<<"Bye for Now"<<endl;
break;
case 1: searchStudent(stdRec,counter);
break;
case 2:showByCourse(stdRec,counter);
break;
case 3://showEligible(stdRec,counter);
break;
case 4:showAll(stdRec,counter);
break;
case 5:update(stdRec,counter);
break;
case 6:add(stdRec,&counter);
break;
case 7:deleteRecord(stdRec,&counter);
break;
}
}while(choice!=0);
system("pause");
}
int menu()
{
int choice;
cout<<"0. Exit"<<endl
<<"1. Search for a student"<<endl
<<"2. List students enrolled in a course"<<endl
<<"3. List students eligible to graduate"<<endl
<<"4. List all students"<<endl
<<"5. Update a student record"<<endl
<<"6. Add a student record"<<endl
<<"7. Delete a student record"<<endl
<<"Your choice ->";
cin>>choice;
return choice;
}
void searchStudent(stdRecord stdRec[],int counter)
{
string ID;
cout<<"Enter the student ID to search-> ";
getline(cin,ID);
for(int i=0;i<counter;i++)
{
if(stdRec[i].studentID.compare(ID)==0)
{
cout<<"The record with the id is:"<<endl;
cout<<"StudentID\tStudentName\tCourseCoce\tCreditPoint"<<endl;
cout<<stdRec[i].studentID<<"\t"<<stdRec[i].studentName<<"\t"<<stdRec[i].courseCode<<"\t"<<stdRec[i].creditPoint<<endl;
cout<<"Have completed the requested process."<<endl;
system("pause");
system("cls");
return;
}
}
char ch;
cout<<"Not Found"<<endl;
cout<<"Do you want search another record(Y/N)";
cin>>ch;
ch=tolower(ch);
if(ch=='y')
searchStudent(stdRec,counter);
else
{
cout<<"Have completed the requested process."<<endl;
system("pause");
system("cls");
}
}
void findCourses(stdRecord stdRec[],int counter)
{
int courses[500];
int coursecount=0;
cout<<" Enter the course code {";
bool found;
for(int i=0;i<counter;i++)
{
found=false;
for(int j=0;j<coursecount;j++)
{
if(stdRec[i].courseCode==courses[j])
{
found=true;
break;
}
}
if(!found)
courses[coursecount++]=stdRec[i].courseCode;
}
cout<<" Enter the course code {";
for(int j=0;j<coursecount-1;j++)
cout<<courses[j]<<", ";
cout<<"or "<<courses[coursecount-1]<<"->";
}
void showByCourse(stdRecord stdRec[],int counter)
{
int courseCode;
findCourses(stdRec,counter);
cin>>courseCode;
cout<<"The student(s) enrolled in the course is(are):"<<endl;
cout<<"StudentID\tStudentName\tCourseCoce\tCreditPoint"<<endl;
int studentsCount=0;
for(int i=0;i<counter;i++)
{
if(stdRec[i].courseCode==courseCode)
{
cout<<stdRec[i].studentID<<"\t"<<stdRec[i].studentName<<"\t"<<stdRec[i].courseCode<<"\t"<<stdRec[i].creditPoint<<endl;
studentsCount++;
}
}
cout<<"There is(are) "<<studentsCount<<" student(s) enrolled in the course."<<endl;
cout<<"Have completed the requested process."<<endl;
system("pause");
system("cls");
}
void showEligible(stdRecord stdRec[],int counter)
{
cout<<"The student(s) eligible to graduate is(are):"<<endl;
int studentsCount=0;
for(int i=0;i<counter;i++)
{
if(stdRec[i].creditPoint>=240)
{
cout<<stdRec[i].studentID<<"\t"<<stdRec[i].studentName<<"\t"<<stdRec[i].courseCode<<"\t"<<stdRec[i].creditPoint<<endl;
studentsCount++;
}
}
cout<<"There is(are) "<<studentsCount<<" graduate student(s)."<<endl;
cout<<"Have completed the requested process."<<endl;
system("pause");
system("cls");
}
void showAll(stdRecord stdRec[],int counter)
{
cout<<"All students are listed below:"<<endl;
for(int i=0;i<counter;i++)
{
cout<<stdRec[i].studentID<<"\t"<<stdRec[i].studentName<<"\t"<<stdRec[i].courseCode<<"\t"<<stdRec[i].creditPoint<<endl;
}
cout<<"Have completed the requested process."<<endl;
system("pause");
system("cls");
}
void update(stdRecord stdRec[],int counter)
{
char keepGoing;
string ID;
do
{
cout<<"Enter the student ID to update-> ";
getline(cin,ID);
bool flag=false;
char choice;
for(int i=0;i<counter;i++)
{
if(stdRec[i].studentID.compare(ID)==0)
{
cout<<"The record with the id is:"<<endl; cout<<"StudentID\tStudentName\tCourseCoce\tCreditPoint"<<endl;
cout<<stdRec[i].studentID<<"\t"<<stdRec[i].studentName<<"\t"<<stdRec[i].courseCode<<"\t"<<stdRec[i].creditPoint<<endl;
cout<<"Enter y or Y to update the course code, others to keep the original one."<<endl;
cin>>choice;
if(choice=='y'||choice=='Y')
{
int courseCode;
findCourses(stdRec,counter);
cin>>courseCode;
stdRec[i].courseCode=courseCode;
}
cout<<"Enter y or Y to update the credit";
cin>>choice;
if(choice=='y'||choice=='Y')
{
int credits;
cout<<"Enter Credit points";
cin>>credits;
stdRec[i].creditPoint=credits;
}
flag=true;
break;
}
}
if(!flag)
{
cout<<"The record with the id "<<ID<<" not Found"<<endl;
}
cout<<"Do you want update another record(Y/N)";
cin>>keepGoing;
keepGoing=tolower(keepGoing);
}while(keepGoing=='y');
cout<<"Have completed the requested process."<<endl;
system("pause");
system("cls");
}
void add(stdRecord stdRec[],int *counter)
{
string studentID;
string studentName;
int courseCode;
int creditPoint;
cout<<"Enter Student ID :";
cin>>studentID;
bool flag=true;
for(int i=0;i<*counter;i++)
{
if(stdRec[i].studentID.compare(studentID)==0)
{
flag=false;
break;
}
}
if(flag)
{
stdRec[*counter].studentID=studentID;
cout<<"Enter Student Name \n";
cin >> studentName;
stdRec[*counter].studentName=studentName;
cout<<"Enter Course Code \n";
cin >> courseCode;
stdRec[*counter].courseCode=courseCode;
cout << "Enter Credit Points \n";
cin >> creditPoint;
stdRec[*counter].creditPoint=creditPoint;
}
else
{
cout<<"Student Id Exists"<<endl;
}
cout<<"Have completed the requested process."<<endl;
system("pause");
system("cls");
}
void deleteRecord(stdRecord stdRec[],int *counter){}
void readIn(stdRecord stdRec[])
{
ifstream file("StudentRecords.txt");
if(file.is_open())
{
stdRecord stdRec[MAXRECORD];
for(int i = 0; i < MAXRECORD; i++)
{
file >> stdRec[i];
}
}
}
答案 0 :(得分：1)
我认为这就是你想要的：
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
using namespace std;
class Student {
public:
//define and/or modify your own constructors here
Student() {}
friend istream& operator >>(istream &input, Student& student);
friend ostream& operator <<(ostream &output, const Student& student);//I gave you this as a BONUS
private:
string firstname;
string lastname;
int grade;
int student_id;
double credit_hours;
double GPA;
};
istream& operator >>(istream &input, Student& student) {
input >> student.firstname
>> student.lastname
>> student.grade
>> student.student_id
>> student.credit_hours
>> student.GPA;
return input;
}
ostream& operator <<(ostream &output, const Student& student) {
output << student.firstname << " "
<< student.lastname << " "
<< student.grade << " "
<< student.student_id << " "
<< student.credit_hours << " "
<< student.GPA << "\n";
return output;
}
int main() {
ifstream ifile;
ifile.open("StudentRecords.txt", ios::in);
if (!ifile.is_open()) {
cerr << "There was an error opening the input file!\n";
exit(0);
}
Student student;
while(ifile >> student) {
cout << student;
}
return 0;
}
根据您拥有的数据，输出：
James Buchanan 1 5640012 30 2.23
Carl Rove 1 12995425 28 1.6
Marie Curie 4 88888888 96 3.5
Micky Mouse 2 8222222 64 1.85
James Madison 3 66633333 88 2.96
Dolly Madison 3 53423445 84 3.24
Pepe LePew 1 73737373 42 2.47
Homer Simpson 4 7223344 105 1.03
Mary Jones 1 9274726 28 2.92
Bloss Sims 4 11111111 100 1.2
正如所料。
唯一的问题是，此代码适用于一个学生，而不是100个。但是，您可以这样做 - 毕竟一切都在适度。您所要做的就是创建一个Student个对象的数组，对它们进行迭代并为它们分配类似于我的方式。