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C Program to design Age Calculator

C Program to design Age Calculator

In this example, we will see a C program to design a Age calculator through which we can calculate someone's age according to it’s date of birth.

Example

/*Age Calculator (C program to calculate age).*/
#include <stdio.h>
#include <time.h>
/*check given year is leap year or not*/
int isLeapYear(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()
{
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;
/* enter date of birth */
printf("Enter your date of birth (DD/MM/YYYY): ");
scanf("%d/%d/%d",&days,&month, &year);
/*get current date.*/
ts = time(NULL);
ct = localtime(&ts);
printf("Current Date: %d/%d/%d\n",
ct->tm_mday, ct->tm_mon + 1, ct->tm_year + 1900);
days = DaysInMon[month - 1] - days + 1;
/* leap year checking*/
if (isLeapYear(year, month)) 
{
days = days + 1;
}
/* calculating age in 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 (isLeapYear((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 age */
printf("\n## Hey you are  %d years %d months and %d days old. ##\n", year, month, days);
return 0;
}

Output:
Enter your date of birth (DD/MM/YYYY): 12/06/1987
Current Date: 26/4/2020
## Hey you are 32 years 10 months and 15 days old. ##