Pointers in Dev C++ vs Visual Studio - c++

Question

I have coded a program that gets the information of employees of a company, when I run it in Dec C++, it does run without any errors, but when I run it in Visual Studio, it returns the following error :
Error C4703 potentially uninitialized local pointer variable 'data' used
and VS asks me to rewrite the pointer like this :
employ *data{};
instaed of : employ *data;
Can anyone please explain why does it happen? and What this {} means here? Is it a thing of C++ or VS?
#include <iostream>
using namespace std;
struct employ {
long int emp_num;
string fn;
string ln;
int work_days;
long int payday;
};
int main()
{
int n=0;
employ *data;
int act;
do {
cout << "___________________________________________________________________________________________________________";
cout << "\n\n\t\tWelcome to the EMPLOTASK!";
cout << "\n\t\tFor doing any of the commands, enter number of that command.";
cout << "\n\t\t_______________________________________________________________";
cout << "\n\n\t\t\ ADD & EDIT : ";
cout << "\n\t\t[1] Add new employees.";
cout << "\n\t\t[2] Edit an existing employee.";
cout << "\n\t\t[3] Delete an existing employee.";
cout << "\n\t\t[4] Print list of all employees.";
cout << "\n\t\t_______________________________________________________________";
cout << "\n\n\t\t\ ACTIONS : ";
cout << "\n\t\t[5] Sort based on their salary.";
cout << "\n\t\t[6] Search for an emplyee.";
cout << "\n\t\t[7] Calculate the average salary.";
cout << "\n\t\t[8] Show maximum and minimum sallary.";
cout << "\n\n\t\tWhat do you want to do?";
cin >> act;
if (act > 8)
cout << "Invalid request!" << endl;
switch (act)
{
case 1: {
cout << "\n\t\t_______________________________________________________________";
cout << "\n\n\t\t\'ADD NEW EMPLOYEES\'";
cout << "\n\t\tEnter number of the employees : ";
cin >> n;
data = new employ[n];
for (int i = 0; i < n; i++)
{
cout << "\n\t\t========== Employee number " << i + 1 << " ==========";
cout << "\n\t\tFirst name : ";
cin >> data[i].fn;
cout << "\t\tLast name : ";
cin >> data[i].ln;
cout << "\t\tEmployee's number : ";
cin >> data[i].emp_num;
cout << "\t\tDays of work : ";
cin >> data[i].work_days;
cout << "\t\tDaily rate : ";
cin >> data[i].payday;
}
cout << "\n\t\t=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=";
cout << "\n\t\tOperatuon's done successfully! =)";
cout << "\n\t\t=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=" << endl;
break;
}
case 2: {
cout << "\n\t\t_______________________________________________________________";
cout << "\n\n\t\t\'EDIT AN EMPLOYEE\'";
cout << "\n\t\tEnter the employee number : ";
int em_num;
cin >> em_num;
int yes = 0;
if (n == 0)
{
cout << "There's no employee!";
}
for (int i = 0; i < n; i++)
{
if (em_num == data[i].emp_num)
{
for (int j = 0; j < n; j++)
{
cout << "\n\t\t========== Edit Employee number " << i + 1 << " ==========";
cout << "\n\t\tFirst name : ";
cin >> data[i].fn;
cout << "\t\tLast name : ";
cin >> data[i].ln;
cout << "\t\tEmployee's number : ";
cin >> data[i].emp_num;
cout << "\t\tDays of work : ";
cin >> data[i].work_days;
cout << "\t\tDaily rate : ";
cin >> data[i].payday;
yes++;
}
}
}
if (yes == 0)
{
cout << "The entered employee number is invalid.";
}
break;
}
default:
break;
}
} while (act != 0);
return 0;
}

Answer 1

Regarding {}: uniform initialization(C++11). It enables you to initialize everything in the same way. It also provides better safety guarantees when it comes to narrowing conversions.
The following code shows some examples.
#include <iostream>
#include <string>
#include <vector>
struct Point
{
Point(float x, float y) : m_x{ x }, m_y{ y } {}
float m_x;
float m_y;
};
int main()
{
int a{ 0 }; // same as a{}
int b{ 1 };
// int c{ 2.0 }; // at least warning, often error
double d{ 3.0 };
char* pc{nullptr}; // same as pc{}
std::string s{ "C++" };
std::vector<int> vi{1, 2, 3, 4, 5};
Point p1{ 3.0f, 4.0f };
}