how many months have 31 days

How many months have 31 days in C++?

To determine the number of months that have 31 days in C++, you can use the ctime library and the struct tm structure. The struct tm structure represents a calendar time, and it has a member called tm_mon that represents the month (0-11, where 0 is January and 11 is December).

Here's an example code snippet that counts the number of months with 31 days:

#include <iostream>
#include <ctime>

int main() {
    int count = 0;
    for (int month = 0; month < 12; month++) {
        // Set the month and year in the struct tm
        struct tm timeinfo = {0};
        timeinfo.tm_mon = month;
        timeinfo.tm_year = 2023 - 1900; // Year is 2023

        // Normalize the struct tm
        mktime(&timeinfo);

        // Check if the month has 31 days
        if (timeinfo.tm_mday == 31) {
            count++;
        }
    }

    std::cout << "Number of months with 31 days: " << count << std::endl;

    return 0;
}

In this code, we iterate over the months from 0 to 11 (representing January to December). For each month, we set the month and year in the struct tm variable timeinfo. We then call mktime to normalize the struct tm. Finally, we check if the tm_mday member of timeinfo is equal to 31, indicating that the month has 31 days. If it does, we increment the count variable.

The output of this code will be the number of months with 31 days in the specified year (2023 in this case).

Please note that this code assumes a Gregorian calendar and may not work correctly for other calendar systems.