How do I get the current date in C++? - c++

Question

I have been trying to get the current date in C++ for a while now and I cannot figure out what I am doing wrong. I have looked at several sites and all of the solutions that I implement I get an error that says, “This function or variable may be unsafe. Consider using localtime_s instead.” I tried several of the solutions found here (including the one below) but I could not get any of them to work. What am I doing wrong?
#include <iostream>
#include <iomanip>
#include <string>
#include <ctime>
using namespace std;
int main()
{
const int SALARY = 18;
const int COMMISSION = .08;
const int BONUS = .03;
int monthlySales;
int appointmentNumber;
time_t t = time(0); // get time now
struct tm * now = localtime(&t);
string name;
//this is where the user adds their name and date
cout << "Please enter the sales representative's name: ";
cin >> name;
cout << "Please enter the number of appointments: ";
cin >> appointmentNumber;
cout << "Please enter the amount of sales for the month: $";
cin >> monthlySales;
//clear screen and execute code
system("cls");
cout << setfill(' ');
cout << "Sales Representative:" << name << endl;
cout << "Pay Date:" << (now->tm_mon + 1) << " " << now->tm_mday << " " << (now->tm_year + 1900) << endl;
cout << "Work Count:" << appointmentNumber << "Sale Amount"
<< monthlySales << endl;
system("pause");
return 0;
}

Answer 1

You can try below code and description beneath it.
#include <iostream>
#include <ctime>
int main ()
{
time_t rawtime;
struct tm * timeinfo;
char buffer[80];
time (&rawtime);
timeinfo = localtime(&rawtime);
strftime(buffer,80,"%d-%m-%Y %I:%M:%S",timeinfo);
std::string str(buffer);
std::cout << str;
return 0;
}
Function
time_t time (time_t* timer);
function returns this value, and if the argument is not a null pointer, it also sets this value to the object pointed by timer.
Parameters
timer
Pointer to an object of type time_t, where the time value is stored.you can also pass it null pointer in case not required
Return Value
The current calendar time as a time_t object.If the function could not retrieve the calendar time, it returns a value of -1.

Answer 2

Here is how I do it:
#include "date/tz.h"
#include <iostream>
int
main()
{
using namespace std::chrono;
std::cout << date::make_zoned(date::current_zone(), system_clock::now()) << '\n';
}
which just output for me:
2016-10-18 10:39:10.526768 EDT
I use this C++11/14 portable, free, open-source library. It is thread-safe. It is based on <chrono>. It is type safe and easy to use. If you need more functionality, this library will do it.
Get the local time in another timezone
Convert local time directly from one timezone to another.
Take leap seconds into account in time computations.
Stream out / stream in time stamps round trip with any precision, and no loss of information.
Search all timezones for a property (such as abbreviation or offset).
This library is being proposed to the C++ standards committee, draft here.

Answer 3

You're getting this warning perhaps because localtime() is not thread-safe. Two instances calling this function might result in some discrepancy.
[...] localtime returns a pointer to a static buffer (std::tm*).
Another thread can call the function and the static buffer could be
overwritten before the first thread has finished reading the content
of the struct std::tm*.

Answer 4

The standard and cross-platform way is to use chrono.
#include <iostream>
#include <chrono>
int main(){
std::time_t now_time = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
std::cout << "Now:" << std::ctime(&now_time);
}

Answer 5

This is another way that could work:
time_t current_time;
struct tm *timeinfo;
time(&current_time);
timeinfo = localtime(&current_time);
string date = asctime(timeinfo);

Answer 6

I greatly appreciate all of your timely the responses. Ultimately I was able to use a variation of Heemanshu Bhalla’s response. I added ‘_CRT_SECURE_NO_WARNINGS’ to the preprocessor definitions by going here then I altered Heemanshu’s code to the following code. This suited my needs.
#include <iostream>
#include <ctime>
#include <string>
using namespace std;
int main()
{
time_t rawtime;
struct tm * timeinfo;
char buffer[80];
time(&rawtime);
timeinfo = localtime(&rawtime);
strftime(buffer, 80, "%m/%d/%Y ", timeinfo);
string str(buffer);
cout << str << endl;
system("PAUSE");
return 0;
}