| Eikcuhc |
11-18-2010 05:55 PM |
Passing ifstream& through derived class's member function
I am running into a problem when trying to compile. The program is supposed to read in text from a file that has the number of students, the student name, the class type, and the grades, then create an output file with the data. I have not gotten to the output part yet, as I run into compiling errors when using g++ to compile the three files with the command:
g++ main.cpp student.cpp student.h
student.cpp: In member function ‘void English::Input(std::ifstream&)’:
student.cpp:66: error: no match for ‘operator>>’ in ‘in1 >> ((English*)this)->English::attend’
student.cpp: In member function ‘void History::Input(std::ifstream&)’:
student.cpp:86: error: no match for ‘operator>>’ in ‘in1 >> ((History*)this)->History::term’
student.cpp: In member function ‘void Math::Input(std::ifstream&)’:
student.cpp:112: error: no match for ‘operator>>’ in ‘in1 >> ((Math*)this)->Math::quiz1’
STUDENT.H
Code:
#include <iostream>
enum coursecode {ENGLISH, HISTORY, MATH, NONE}; // None is used only for initializing class
class Student
{
public:
virtual double Finalavg() = 0;
Student();
void Setstudent(const char* f, const char* l, const char* cc);
coursecode Returncourse();
protected:
char first[20];
char last[20];
coursecode course;
double finalexam,
finalavg;
};
class English : public Student
{
public:
English();
double Finalavg();
void Input(std::ifstream& in1);
private:
double attend,
proj,
mid;
};
class History : public Student
{
public:
History();
double Finalavg();
void Input(std::ifstream& in1);
private:
double term,
mid;
};
class Math : public Student
{
public:
Math();
double Finalavg();
void Input(std::ifstream& in1);
private:
double quiz1,
quiz2,
quiz3,
quiz4,
quiz5,
quizavg,
test1,
test2;
};
STUDENT.CPP
Code:
#include <iostream>
#include <cstring>
#include <iomanip>
#include "student.h"
using namespace std;
Student::Student()
{
char word1[] = " ";
char word2[] = " ";
strncpy(first, word1, 20);
strncpy(last, word2, 20);
course = NONE;
finalexam = 0;
finalavg = 0;
}
void Student::Setstudent(const char* f, const char* l, const char* cc)
{
char temp[7] = "NONE";
strncpy(temp,cc,1);
// Selects the cource code based on what is input
// Since all the courses have a different starting letter,
// we only need to compare the first letter
switch(temp[0])
{
case 'E':
case 'e':
course = ENGLISH;
break;
case 'H':
case 'h':
course = HISTORY;
break;
case 'M':
case 'm':
course = MATH;
break;
default:
course = NONE;
break;
}
strncpy(first, f, 20);
strncpy(last, l, 20);
}
coursecode Student::Returncourse()
{
return course;
}
// ====================== ENGLISH ============================
English::English()
{
attend = 0;
proj = 0;
mid = 0;
}
void English::Input(ifstream& in1)
{
in1 >> attend >> proj >> mid >> finalexam;
}
double English::Finalavg()
{
finalavg = (attend * .10) + (proj * .30)
+ (mid * .30) + (finalexam * .30);
return finalavg;
}
// ====================== HISTORY ============================
History::History()
{
term = 0;
mid = 0;
}
void History::Input(ifstream& in1)
{
in1 >> term >> mid >> finalexam;
}
double History::Finalavg()
{
finalavg = (term * .25) + (mid * .35)
+ (finalexam * .40);
return finalavg;
}
// ========================== MATH ===========================
Math::Math()
{
quiz1 = 0;
quiz2 = 0;
quiz3 = 0;
quiz4 = 0;
quiz5 = 0;
quizavg = 0;
test1 = 0;
test2 = 0;
}
void Math::Input(ifstream& in1)
{
in1 >> quiz1 >> quiz2 >> quiz3 >> quiz4
>> quiz5 >> test1 >> test2 >> finalexam;
}
double Math::Finalavg()
{
quizavg = (quiz1 + quiz2 + quiz3 + quiz4 + quiz5) / 5;
finalavg = (quizavg * .15) + (test1 * .25)
+ (test2 * .25) + (finalexam * .35);
return finalavg;
}
MAIN.CPP
Code:
#include <iostream>
#include <fstream>
#include "student.h"
using namespace std;
int main()
{
char input; // Input file name
char output; // Output file name
char temp[5] = "null"; // Used to pick up any white space
ifstream in1;
ofstream out1;
int numstudents; // Used to pick up amount of students in file
cout << "Please enter the name of the input file.\n"
<< "Filename: ";
cin >> input;
cout << "Please enter the name of the output file.\n"
<< "Filename: ";
cin >> output;
// First we must input the first line, telling us how many students are
// within the file
in1 >> numstudents;
Student** list = new Student* [numstudents];
in1.getline(temp,2);
for (int i = 0; i < numstudents; i++)
{
char f[20],
l[20],
cc[20];
in1.get(l, 20, ',');
in1.getline(temp, 2, ' ');
in1.getline(f, 20);
in1.get(cc, 20, ' ');
if ((cc[0] == 'E') || (cc[0] == 'e'))
{
English* eng = new English;
eng->Setstudent(f, l, cc);
eng->Input(in1);
list[i] = eng;
}
else if ((cc[0] == 'H') || (cc[0] == 'h'))
{
History* hist = new History;
hist->Setstudent(f, l, cc);
hist->Input(in1);
list[i] = hist;
}
else if ((cc[0] == 'M') || (cc[0] == 'm'))
{
Math* math = new Math;
math->Setstudent(f, l, cc);
math->Input(in1);
list[i] = math;
}
}
}
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