How to calculate someone's age, in days, months and years using a C program?

Question

Input
2026
Output
261

Answer 1

Here is a code for your problem

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

  /* checks whether the given input is leap year feb or not */
  int leapYearFeb(int year, int mon) {
        int flag = 0;
        if (year % 100 == 0) {
                if (year % 400 == 0) {
                        if (mon == 2) {
                                flag = 1;
                        }
                }
        } else if (year % 4 == 0) {
                if (mon == 2) {
                        flag = 1;
                }
        }
        return (flag);
  }

  int main() {
        /* days in months */
        int daysInMon[] = {31, 28, 31, 30, 31, 30,
                           31, 31, 30, 31, 30, 31};
        int days, month, year;
        char dob[100];
        time_t ts;
        struct tm *ct;

        /* get the date of birth from the user */
        printf("Enter your days of birth:");
        fgets(dob, 100, stdin);
        sscanf(dob, "%d/%d/%d", &days, &month, &year);
        ts = time(NULL);
        ct = localtime(&ts);
        /* scan the year, month and year from the input string */
        printf("Current Date: %d/%d/%d\n",
                ct->tm_mday, ct->tm_mon + 1, ct->tm_year + 1900);

        days = daysInMon[month - 1] - days + 1;

        /* checking whether month is leap year feb - 29 days*/
        if (leapYearFeb(year, month)) {
                days = days + 1;
        }

        /* calculating the no of days, years and months */
        days = days + ct->tm_mday;
        month = (12 - month) + (ct->tm_mon);
        year = (ct->tm_year + 1900) - year - 1;

        /* checking for leap year feb - 29 days */
        if (leapYearFeb((ct->tm_year + 1900), (ct->tm_mon + 1))) {
                if (days >= (daysInMon[ct->tm_mon] + 1)) {
                        days = days - (daysInMon[ct->tm_mon] + 1);
                        month = month + 1;
                }
        } else if (days >= daysInMon[ct->tm_mon]) {
                days = days - (daysInMon[ct->tm_mon]);
                month = month + 1;
        }

        if (month >= 12) {
                year = year + 1;
                month = month - 12;
        }

        /* print the result */
        printf("Age: %d year %d months and %d days\n", year, month, days);
        return 0;
  }