Formatting SYSTEMTIME

Hello,

I am having a hard time displaying the current time (with AM/PM and putting the correct '0' padding.

12:01 PM
7:08 AM
2:26 PM

Code:

---

        SYSTEMTIME st;
        GetLocalTime(&st);

        WORD hour = st.wHour;
        WORD minute = st.wMinute;
        WORD seconds = st.wSecond;

        TCHAR _time[MAX_PATH] = TEXT("\0");

        wsprintf(_time, TEXT("%d:%1d %1d"), hour, minute, seconds);

---

The code above does not place the '0' for a single digit minute and also does not display AM PM

How can i do this?

Normally, you would use a format like "%02d" to print values from 00 to 59 say.

What about the AM/PM format?

You could use standard functions instead of windows functions:

Code:

---

#include <stdio.h>
#include <time.h>

int main() {
    struct tm *timeinfo;
    char buffer[80];
    time_t tim = time(NULL);

    timeinfo = localtime(&tim);
    strftime(buffer, 80, "%I:%M%p", timeinfo);
    puts(buffer);

    return 0;
}

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Quote:

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Originally Posted by EverydayDiesel

The code above does not place the '0' for a single digit minute and also does not display AM PM

---

Why would you want that in the first place? The API returns the time in 24h format.
Also, in C++, you would do it this way to avoid system-dependent calls (code being entirely portable):

Code:

---

#include <iostream>
#include <ctime>
#include <chrono>

int main()
{
        auto today = std::chrono::system_clock::now();
        auto tt = std::chrono::system_clock::to_time_t(today);
        std::cout << "Today is: " << ctime(&tt);
        return 0;
}

---

Also, in C++, do not use wsprintf and do not use char/wchar_t/TCHAR. You are strongly recommended to use std::string/std::wstring and std::stringstream/std::wstringstream.

Quote:

---

Originally Posted by Elysia

Why would you want that in the first place? The API returns the time in 24h format.
Also, in C++, you would do it this way to avoid system-dependent calls (code being entirely portable):

Code:

---

#include <iostream>
#include <ctime>
#include <chrono>

int main()
{
    auto today = std::chrono::system_clock::now();
    auto tt = std::chrono::system_clock::to_time_t(today);
    std::cout << "Today is: " << ctime(&tt);
    return 0;
}

---

Also, in C++, do not use wsprintf and do not use char/wchar_t/TCHAR. You are strongly recommended to use std::string/std::wstring and std::stringstream/std::wstringstream.

---

I dont want the format to be in 24 hour format. I want to display as 1 2 3 4 5 6 7 8 9 10 11 12 1PM 2PM 3PM etc

the code above tells me it is unsafe?

Code:

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error C4996: 'ctime': This function or variable may be unsafe. Consider using ctime_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS

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Changing to ctime_s creates more errors because it is looking for a buffer, buff length and time

Code:

---

#include <iostream>
#include <ctime>
#include <chrono>
#include <iomanip>

int main()
{
        auto today = std::chrono::system_clock::now();
        auto tt = std::chrono::system_clock::to_time_t(today);
        auto * localtime = std::localtime(&tt);
        std::cout << "Today is: " << std::put_time(localtime, "%Y-%m-%d %I:%M:%S %p") << "\n"; // 12h clock
        std::cout << "Today is: " << std::put_time(localtime, "%Y-%m-%d %H:%M:%S") << "\n"; // 24h clock
        return 0;
}

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Seeing as localtime, ctime, etc are C functions, they are unsafe by nature. Hence Microsoft made safer versions of them because they required extra parameters (or input information) to be made safer.
Ideally, you should use them, but beware that they aren't portable (they won't compile with anything but Microsoft's compiler), so it's really up to you. You must learn to use them correctly, though, or they're no safer than the standard C functions.
It is possible to easily map these "newer" functions to the older, unsafer versions by creating wrapper functions if you're going to port it, too, just so you know.

Actually since ctime() is considered by some to obsolete even in C, you should be using the strftime() function instead. And just because a function has C origins does not in it's self make a function unsafe.

Jim