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#include <iostream>
#include <fstream>
using namespace std;
struct Student
{
char* name;
int fn;
int gradesCount;
double averageGrade;
};
void print(const Student& st)
{
cout << st.name << " " << st.fn << " " << st.gradesCount << " " << st.averageGrade << endl;
}
Student createStudent(const char* name, int fn, int gradesCount, double avGrade)
{
Student obj;
size_t nameLen = strlen(name);
obj.name = new char[nameLen + 1];
strcpy(obj.name, name);
obj.fn = fn;
obj.gradesCount = gradesCount;
obj.averageGrade = avGrade;
return obj;
}
void saveStudentToFile(ofstream& f, const Student& st)
{
size_t nameLen = strlen(st.name);
f.write((const char*)&nameLen, sizeof(nameLen)); //first we write the size of the name!
f.write(st.name, nameLen);
f.write((const char*)&st.fn, sizeof(st.fn));
f.write((const char*)&st.gradesCount, sizeof(st.gradesCount));
f.write((const char*)&st.averageGrade, sizeof(st.averageGrade));
}
Student readStudentFromFile(ifstream& f)
{
Student res;
size_t nameLen;
f.read((char *)&nameLen, sizeof(nameLen)); //first we read the size of the name!
res.name = new char[nameLen + 1];
f.read(res.name, nameLen);
res.name[nameLen] = '\0';
f.read((char *)&res.fn, sizeof(res.fn));
f.read((char*)&res.gradesCount, sizeof(res.gradesCount));
f.read((char*)&res.averageGrade, sizeof(res.averageGrade));
return res;
}
void freeStudent(Student& s)
{
delete[] s.name;
s.averageGrade = s.fn = s.gradesCount = 0;
}
const int UNI_NAME_MAX = 32;
struct Uni
{
char name[UNI_NAME_MAX];
size_t studentsCount;
Student* students;
};
void saveUniToFile(ofstream& f, const Uni& uni)
{
f.write(uni.name, sizeof(uni.name));
f.write((const char*)&uni.studentsCount, sizeof(uni.studentsCount)); //first we write how many students we have!
for (int i = 0; i < uni.studentsCount; i++)
saveStudentToFile(f, uni.students[i]);
}
void readUniFromFile(ifstream& f, Uni& uni)
{
f.read(uni.name, sizeof(uni.name));
f.read((char*) &uni.studentsCount, sizeof(uni.studentsCount)); //we read how many students are saved in the file!
uni.students = new Student[uni.studentsCount];
for (int i = 0; i < uni.studentsCount; i++)
uni.students[i] = readStudentFromFile(f);
}
void freeUni(Uni& uni)
{
for (int i = 0; i < uni.studentsCount; i++)
freeStudent(uni.students[i]);
strcpy(uni.name, "");
uni.studentsCount = 0;
}
void print(const Uni& u)
{
cout << u.name << " " << u.studentsCount << endl;
for (int i = 0; i < u.studentsCount; i++)
print(u.students[i]);
}
int main()
{
{ //Creating an university and saving to file
Uni u;
strcpy(u.name, "FMI");
u.studentsCount = 3;
u.students = new Student[u.studentsCount];
u.students[0] = createStudent("Ivan", 81234, 3, 4.5);
u.students[1] = createStudent("Angel", 12345, 4, 5);
u.students[2] = createStudent("Mariq", 81234, 5, 5.5);
ofstream f("uni.dat", ios::binary);
if (!f.is_open())
{
cout << "Error" << endl;
return -1;
}
saveUniToFile(f, u);
freeUni(u);
}
{ //Reading an university from file
Uni myUni;
ifstream f("uni.dat", ios::binary);
if (!f.is_open())
{
cout << "Error" << endl;
return -1;
}
readUniFromFile(f, myUni);
print(myUni);
f.close();
freeUni(myUni);
}
}
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