This is all my code I want to sort the records when display all students using option 2 in the main menu this code returning me the data as it was saved means unsorted.
#include<iostream>
#include<fstream>
#include<iomanip>
#include<vector>
using namespace std;
class student
{
int Idnum;
char Name[25];
char Course[30];
int Result;
public:
void getdata();
void showdata() const;
void show_tabular() const;
int getIDNum() const;
};
void student::getdata()
{
cout << "\nEnter student's ID Number: ";//prints Enter student's ID Number
cin >> Idnum;
cout << "\n\nEnter student's Name: ";//prints Enter student's Name
cin.ignore();//to ignore from the input buffer
cin.getline(Name, 25);
cout << "\nEnter student's Course: ";//prints Enter student's Course
cin >> Course;
cout << "\nEnter student's Result: ";//prints Enter student's Result
cin >> Result;
}
void student::showdata() const
{
cout << "\nID Number: " << Idnum;//prints ID Number
cout << "\nName: " << Name;//prints Name
cout << "\nCourse: " << Course;//prints Course
cout << "\nResult: " << Result;//prints Result
}
void student::show_tabular() const
{
cout << Idnum << setw(6) << " " << Name << setw(20) << Course << setw(20) << Result << setw(4) << endl;
}
int student::getIDNum() const
{
return Idnum;
}
void SaveStudent();
void displayAll();
void Searchdisplay(int);
void modifyStudent(int);
void deleteStudent(int);
void DisplayResult();
This is the code for creating a student.dat file if it does not exist here and if will exist then write a new student record but this will not sort the records as I want.
void write_student()//to create students record
{
student st;
ofstream outFile;
ifstream inFile;
outFile.open("student.dat", ios::binary | ios::app);//opens file student.dat
st.getdata();
//cout << st.getIDNum();
if (inFile.seekg(reinterpret_cast<char *> (&st)))
{
}
outFile.write(reinterpret_cast<char *> (&st), sizeof(student));//writes the file
outFile.close();//closes the file
cout << "\n\nStudent record Has Been Created ";
cin.ignore();
cin.get();
}
This is the place where I am showing my student's records but this will show unsorted records and I want it in a sorted way means ascending order by roll no of students.
void display_all()//to display the student record
{
student st;
ifstream inFile;
inFile.open("student.dat", ios::binary);//opens file student.dat
if (!inFile)
{
cout << "File could not be open !! Press any Key...";
cin.ignore();//to ignore from the input buffer
cin.get();//to access the char
return;
}
cout << "\n\n\n\t\tDISPLAY ALL RECORD !!!\n\n";
while (inFile.read(reinterpret_cast<char *> (&st), sizeof(st)))
{
st.showdata(); //function to show data on screen
cout << "\n\n====================================\n";
}
inFile.close();//closes the file
cin.ignore();
cin.get();
}
void display_sp(int n)//to search for student record
{
student st;
ifstream inFile;
inFile.open("student.dat", ios::binary);//opens file student.dat
if (!inFile)
{
cout << "File could not be open !! Press any Key...";
cin.ignore();
cin.get();
return;
}
bool flag = false;//for false condition
while (inFile.read(reinterpret_cast<char *> (&st), sizeof(student)))
{
if (st.getIDNum() == n)
{
st.showdata();
flag = true;
}
}
inFile.close();//closes the file
if (flag == false)
cout << "\n\nrecord not exist";//prints record not exist
cin.ignore();
cin.get();
}
void modify_student(int n)//to modify the record
{
bool found = false;//for false condition
student st;
fstream File;
File.open("student.dat", ios::binary | ios::in | ios::out);//opens the file student.dat
if (!File)
{
cout << "File could not be open !! Press any Key...";
cin.ignore();
cin.get();
return;
}
while (!File.eof() && found == false)
{
File.read(reinterpret_cast<char *> (&st), sizeof(student));//reads the file
if (st.getIDNum() == n)
{
st.showdata();
cout << "\n\nPlease Enter The New Details of student" << endl;
st.getdata();
int pos = (-1)*static_cast<int>(sizeof(st));
File.seekp(pos, ios::cur);
File.write(reinterpret_cast<char *> (&st), sizeof(student));
cout << "\n\n\t Record Updated";
found = true;
}
}
File.close();//closes the file
if (found == false)
cout << "\n\n Record Not Found ";
cin.ignore();
cin.get();
}
void delete_student(int n)//to delete the student record
{
student st;
ifstream inFile;
inFile.open("student.dat", ios::binary);//opens the student.dat file
if (!inFile)
{
cout << "File could not be open !! Press any Key...";
cin.ignore();
cin.get();
return;
}
ofstream outFile;
outFile.open("Temp.dat", ios::out);//to open another file
inFile.seekg(0, ios::beg);
while (inFile.read(reinterpret_cast<char *> (&st), sizeof(student)))
{
if (st.getIDNum() != n)
{
outFile.write(reinterpret_cast<char *> (&st), sizeof(student));
}
}
outFile.close();//to open another file
inFile.close();
remove("student.dat");
rename("Temp.dat", "student.dat");
cout << "\n\n\tRecord Deleted ..";
cin.ignore();
cin.get();
}
int main()
{
char ch;
int num;
cout.setf(ios::fixed | ios::showpoint);
cout << setprecision(2);
do
{
system("cls");
cout << "\t===================================";
cout << "\n\n\t1. CREATE STUDENT RECORD";
cout << "\n\n\t2. DISPLAY ALL STUDENTS RECORDS";
cout << "\n\n\t3. SEARCH STUDENT RECORD ";
cout << "\n\n\t4. MODIFY STUDENT RECORD";
cout << "\n\n\t5. DELETE STUDENT RECORD";
cout << "\n\n\t6. EXIT";
cout << "\n\n\t===================================";
cout << "\n\n\tPlease Enter Your Choice (1-6): ";
cin >> ch;
system("cls");
switch (ch)//uses switch casee
{
case '1': write_student(); break;
case '2': display_all(); break;
case '3': cout << "\n\n\tPlease Enter Student's ID number: "; cin >> num;
display_sp(num); break;
case '4': cout << "\n\n\tPlease Enter Student's ID number: "; cin >> num;
modify_student(num); break;
case '5': cout << "\n\n\tPlease Enter Student's ID number: "; cin >> num;
delete_student(num); break;
case '6': exit(0);;
default: cout << "\a";
}
} while (ch != '6');
return 0;
}
