How to compare user date with system date in c++?

Question

I have taken in date from the user in DD/MM/YEAR formate but I want to compare it with system date and want to know whether the date entered by the user is in future or past !!

#include <iostream>
#include <ctime>

int main ()
{      
    char date [10],sysdate[10];
    cout<<"enter Date";           
    cin>>date;                   //for taking date from user
    _strdate(sysdate);      //for getting system date(given in DD/MM/YY    
    cout<< sysdate;        //prints system date    
}

The C++ `chrono` facility does not appear to provide any support for dealing with years, months, and days. You can use the C `mktime()` function. — jxh, Jan 22 '15 at 18:41
It is often OS specific. On POSIX systems consider [strptime](http://man7.org/linux/man-pages/man3/strptime.3.html) & [strftime](http://man7.org/linux/man-pages/man3/strftime.3.html) etc.... — Basile Starynkevitch, Jan 22 '15 at 18:57

score 0 · Answer 1 · answered Jan 22 '15 at 18:35

0

If you are dealing strictly with date strings (instead of datetime_ttimestamps or datetmstructures), then you can directly compare date strings of the format "YY/MM/DD" to determine whether one comes before or after the other.

The format you are using ("DD/MM/YY") does not allow this kind of direct string comparison.

answered Jan 22 '15 at 18:35

David R Tribble

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But 'sydate' gives system date in DD/MM/YY format so how can i change that? – user2891112 Jan 22 '15 at 19:36
You could rearrange the digits within the `sysdate` value to create a new string, and use that one for the comparison. – David R Tribble Jan 22 '15 at 21:36
how do i compare it even after rearranging it in YY/DD/MM? – user2891112 Jan 23 '15 at 07:47
Using `std::strcmp()` or something similar. – David R Tribble Jan 23 '15 at 21:44

score 0 · Answer 2 · answered Jan 22 '15 at 18:55

Watch this example then it wont be hard to compare user date with system date

#include <iostream>
#include <ctime>

using namespace std;

int main( )
{
   // current date/time based on current system
   time_t now = time(0);


   tm *ltm = localtime(&now);

   // print various components of tm structure.
   cout << "Year: "<< 1900 + ltm->tm_year << endl;
   cout << "Month: "<< 1 + ltm->tm_mon<< endl;
   cout << "Day: "<<  ltm->tm_mday << endl;

  }

How to compare user date with system date in c++?

2 Answers2