How can you convert date formats in the C programming l…

In C language, you can use the strftime function to convert date formats. The prototype of the strftime function is as follows:

size_t strftime(char *str, size_t maxsize, const char *format, const struct tm *timeptr);

Explanation of parameters:

1. str: pointer to a string for storing the conversion result.
2. maximum size: the maximum length of the string pointed to by str.
3. String for changing format.
4. timeptr: pointer to a tm structure, indicating the date and time to be converted.

Below is an example of converting the current date and time into a specified format string:

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

int main() {
    time_t rawtime;
    struct tm *timeinfo;
    char buffer[80];

    time(&rawtime);
    timeinfo = localtime(&rawtime);

    strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", timeinfo);
    printf("Formatted date and time: %s\n", buffer);

    return 0;
}

Output: result

Formatted date and time: 2022-01-01 12:34:56

Different format specifiers can be used in the third parameter of the strftime function to define various date and time formats. For example, %Y represents a four-digit year, %m represents a two-digit month, %d represents a two-digit day, %H represents hours in 24-hour format, %M represents minutes, %S represents seconds. More detailed format specifiers can be found in the relevant documentation for the C language.