C++ How can i get all line in binary files? - c++

Question

my code in below.
int main() {
Employee* employee = new Employee();
cout << "Creating File..." << endl;
fstream file("deneme1.txt",ios::out|ios::binary|ios::ate);
for(int i=0;i<10;i++){
if(i<4){
string name;
float salary;
int yearHired;
cout<<"Enter Name: ";
cin>>name;
cout<<"Enter Salary: ";
cin>>salary;
cout<<"Enter Year Hired: ";
cin>>yearHired;
employee->set_id(i);
employee->set_name(name);
employee->set_salary(salary);
employee->set_yearHired(yearHired);
file.write((char*)&employee,sizeof(employee));
file.close();
}
}
file.open("deneme1.txt",ios::in|ios::out|ios::binary);
file.seekg(0);
while((file.read((char*)&employee,sizeof(employee)))) {
cout << employee->get_id();
}
}
I have binary file named "deneme1.txt". I record four object to "deneme1.txt". I want to get all line of "deneme1.txt" in while loops, but I can only get the last line.(So output is
"Creating File...
3"
)
How can I get all the line in the file? Maybe the file has only one object?
my class in below
class Employee
{
private:
string name;
int id;
float salary;
int yearHired;
public:
void set_name(string n)
{
this->name = n;
}
void set_id(int i)
{
this->id = i;
}
string get_name()
{
return name;
}
int get_id()
{
return id;
}
void set_salary(float s)
{
this->salary = s;
}
float get_salary()
{
return salary;
}
void set_yearHired(int y)
{
this->yearHired = y;
}
int get_yearHired()
{
return yearHired;
}
};
I expect that output be "0 1 2 3"

Answer 1

After some cleanup, this should not have any undefined behavior.
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <string>
class Employee {
private:
std::string name;
int id;
float salary;
int yearHired;
public:
Employee(const std::string &name, int id, float salary, int yearHired) : name(name), id(id), salary(salary),
yearHired(yearHired) {}
Employee(Employee const&) = delete;
Employee& operator=(Employee const&) = delete;
int get_id() const {
return id;
}
};
int main() {
std::cout << "Creating File..." << std::endl;
{
std::ofstream file("deneme1.txt", std::ios::out | std::ios::binary | std::ios::ate);
std::string name;
for (int i = 0; i < 4; i++) {
float salary;
int yearHired;
std::cout << "Enter Name: ";
std::cin >> name;
std::cout << "Enter Salary: ";
std::cin >> salary;
std::cout << "Enter Year Hired: ";
std::cin >> yearHired;
Employee employee(name, i, salary, yearHired);
file.write((char *) &employee, sizeof(employee));
}
} // file.close();
std::ifstream file("deneme1.txt", std::ios::in | std::ios::binary);
char* employeeData = new char[sizeof(Employee)];
{
const Employee &employee = *reinterpret_cast<const Employee *>(employeeData);
while ((file.read((char *) &employee, sizeof(employee)))) {
std::cout << employee.get_id();
}
}
delete[]employeeData;
return EXIT_SUCCESS;
}