Step by Step solution about How to resolve the algorithm Palindrome dates step by step in the C programming language

This C code finds and prints the next 15 palindrome dates, which are dates that read the same forwards and backwards. Here's a detailed explanation:

1. Header Inclusions:

   • <stdbool.h>: Includes the bool data type.
   • <stdio.h>: Provides input/output functions.
   • <string.h>: Contains string manipulation functions.
   • <time.h>: For date and time functions.

2. is_palindrome Function:

   • This function checks if a given string str is a palindrome (reads the same forwards and backwards).
   • It uses a loop to compare characters at corresponding positions from the beginning and end of the string.
   • If any pair of characters doesn't match, it returns false.
   • Otherwise, it returns true.

3. main Function:

   • Variables:
     • time_t timestamp: Stores the current timestamp.
     • const int seconds_per_day: Represents the number of seconds in a day.
     • int count: Keeps track of the number of palindrome dates to find (initially set to 15).
     • char str[32]: A buffer to store formatted dates.
   • Output:
     • The program prints the heading "Next 15 palindrome dates:".
   • Loop:
     • It enters a loop that continues as long as count is greater than 0.
     • Inside the loop, the timestamp is incremented by seconds_per_day to move to the next day.
     • The gmtime function is used to convert the timestamp to a struct tm representing the date and time.
     • The strftime function formats the date into the str buffer using the format "%Y%m%d", which represents the date in YYYYMMDD format.
     • The is_palindrome function is called to check if the formatted date is a palindrome.
     • If it's a palindrome, the date is formatted using the "%F" format (YYYY-MM-DD) and printed.
     • The count is decremented.

4. Return:

   • The main function returns 0, indicating successful program execution.

This program iterates through the next 15 days starting from the current time, checking if each day's date is a palindrome, and prints the palindrome dates it finds.

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

bool is_palindrome(const char* str) {
    size_t n = strlen(str);
    for (size_t i = 0; i + 1 < n; ++i, --n) {
        if (str[i] != str[n - 1])
            return false;
    }
    return true;
}

int main() {
    time_t timestamp = time(0);
    const int seconds_per_day = 24*60*60;
    int count = 15;
    char str[32];
    printf("Next %d palindrome dates:\n", count);
    for (; count > 0; timestamp += seconds_per_day) {
        struct tm* ptr = gmtime(&timestamp);
        strftime(str, sizeof(str), "%Y%m%d", ptr);
        if (is_palindrome(str)) {
            strftime(str, sizeof(str), "%F", ptr);
            printf("%s\n", str);
            --count;
        }
    }
    return 0;
}