Program to calculate age

Given the current date and birth date, find the present age. 

Examples:

Input : Birth date = 07/09/1996 
        Present date = 07/12/2017
Output : Present Age = Years: 21  Months: 3  Days: 0
t Age = Years: 7  Months: 11  Days: 21

While calculating the difference in two dates we need to just keep track of two conditions that will do.  

• If the current date is less than that of the birth date, then that month is not counted, and for subtracting dates we add number of month days to the current date so as to get the difference in the dates.
• If the current month is less than the birth month, then the current year is not taken into count as this year has not been completed and for getting the difference of months, we subtract by adding 12 to the current month.
• At the end we just need to subtract the days, months and years to get the difference after the two conditions are dealt with.

Below is the implementation of the above approach is as follows:   

C++

// c program for age calculator
#include <stdio.h>
#include <stdlib.h>

// function to calculate current age
void findAge(int current_date, int current_month,
             int current_year, int birth_date,
             int birth_month, int birth_year)
{
    // days of every month
    int month[] = { 31, 28, 31, 30, 31, 30,
                    31, 31, 30, 31, 30, 31 };

    // if birth date is greater than current date
    // then do not count this month and add 30
    // to the date so as to subtract the date and
    // get the remaining days
    if (birth_date > current_date) {
        current_date
            = current_date + month[birth_month - 1];
        current_month = current_month - 1;
    }

    // if birth month exceeds current month, then do
    // not count this year and add 12 to the month so
    // that we can subtract and find out the difference
    if (birth_month > current_month) {
        current_year = current_year - 1;
        current_month = current_month + 12;
    }

    // calculate date, month, year
    int calculated_date = current_date - birth_date;
    int calculated_month = current_month - birth_month;
    int calculated_year = current_year - birth_year;

    // print the present age
    printf("Present Age\nYears: %d  Months: %d  Days:"
           " %d\n",
           calculated_year, calculated_month,
           calculated_date);
}

// driver code to check the above function
int main()
{
    // current dd// mm/yyyy
    int current_date = 7;
    int current_month = 12;
    int current_year = 2017;

    // birth dd// mm// yyyy
    int birth_date = 16;
    int birth_month = 12;
    int birth_year = 2009;

    // function call to print age
    findAge(current_date, current_month, current_year,
            birth_date, birth_month, birth_year);
    return 0;
}

Java

// Java program for age calculator
import java.io.*;

class GFG {
    static void findAge(int current_date, int current_month,
                    int current_year, int birth_date,
                    int birth_month, int birth_year)
    {
        int month[] = { 31, 28, 31, 30, 31, 30, 31,
                             31, 30, 31, 30, 31 };

        // if birth date is greater than current
        // date, then do not count this month
        // and add 30 to the date so as to subtract
        // the date and get the remaining days
        if (birth_date > current_date) {
            current_month = current_month - 1;
            current_date = current_date + month[birth_month - 1];
        }

        // if birth month exceeds current month,
        // then do not count this year and add
        // 12 to the month so that we can subtract
        // and find out the difference
        if (birth_month > current_month) {
            current_year = current_year - 1;
            current_month = current_month + 12;
        }

        // calculate date, month, year
        int calculated_date = current_date - birth_date;
        int calculated_month = current_month - birth_month;
        int calculated_year = current_year - birth_year;

        // print the present age
        System.out.println("Present Age");
        System.out.println("Years: " + calculated_year +
              " Months: " + calculated_month + " Days: " +
              calculated_date);
    }
    public static void main(String[] args)
    {
        // present date
        int current_date = 7;
        int current_month = 12;
        int current_year = 2017;

        // birth dd// mm// yyyy
        int birth_date = 16;
        int birth_month = 12;
        int birth_year = 2009;

        // function call to print age
        findAge(current_date, current_month, current_year,
              birth_date, birth_month, birth_year);
    }
}

Python

# Python program to calculate range

def findAge(current_date, current_month, current_year,
            birth_date, birth_month, birth_year):

    # if birth date is greater than current date
    # then do not count this month and add 30 to the date so
    # as to subtract the date and get the remaining days

    month =[31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
    if (birth_date > current_date):
        current_month = current_month - 1
        current_date = current_date + month[birth_month-1]


    # if birth month exceeds current month, then
    # donot count this year and add 12 to the
    # month so that we can subtract and find out
    # the difference
    if (birth_month > current_month):
        current_year = current_year - 1;
        current_month = current_month + 12;

    # calculate date, month, year
    calculated_date = current_date - birth_date;
    calculated_month = current_month - birth_month;
    calculated_year = current_year - birth_year;

    # print present age
    print"Present Age"
    print("Years:", calculated_year, "Months:",
         calculated_month, "Days:", calculated_date)

# driver code
current_date = 7
current_month = 12
current_year = 2017

# birth dd//mm//yyyy
birth_date = 16
birth_month = 12
birth_year = 2009

findAge(current_date, current_month, current_year,
        birth_date, birth_month, birth_year)

C#

// C# program for age calculator
using System;

class GFG {

    static void findAge(int current_date,
                       int current_month,
                        int current_year,
                          int birth_date,
                         int birth_month,
                          int birth_year)
    {
        int []month = { 31, 28, 31, 30, 31, 30,
                      31, 31, 30, 31, 30, 31 };

        // if birth date is greater than
        // current date, then do not
        // count this month and add 30 to the
        // date so as to subtract the date and
        // get the remaining days
        if (birth_date > current_date)
        {
            current_month = current_month - 1;

            current_date = current_date
                      + month[birth_month - 1];
        }

        // if birth month exceeds current month,
        // then do not count this year and add
        // 12 to the month so that we can
        // subtract and find out the difference
        if (birth_month > current_month)
        {
            current_year = current_year - 1;
            current_month = current_month + 12;
        }

        // calculate date, month, year
        int calculated_date = current_date
                                 - birth_date;

        int calculated_month = current_month
                                - birth_month;

        int calculated_year = current_year
                                 - birth_year;

        // print the present age
        Console.WriteLine("Present Age");
        Console.WriteLine("Years: "
                           + calculated_year +
                " Months: " + calculated_month
               + " Days: " + calculated_date);
    }

    // driver code to check the above function
    public static void Main()
    {

        // present date
        int current_date = 7;
        int current_month = 12;
        int current_year = 2017;

        // birth dd// mm// yyyy
        int birth_date = 16;
        int birth_month = 12;
        int birth_year = 2009;

        // function call to print age
        findAge(current_date, current_month,
                   current_year, birth_date,
                   birth_month, birth_year);
    }
}

//This code is contributed by vt_m.

PHP

<?php
// PHP program for
// age calculator

// function to calculate
// current age
function findAge(int $current_date, int $current_month,
                 int $current_year, int $birth_date,
                 int $birth_month, int $birth_year)
{

    // days of every month
    $month = array(31, 28, 31, 30, 31, 30,
                   31, 31, 30, 31, 30, 31 );

    // if birth date is greater
    // than current date
    // then do not count this
    // month and add 30 to the
    // date so as to subtract
    // the date and get the
    // remaining days
    if ($birth_date > $current_date)
    {
        $current_date = $current_date +
                        $month[$birth_month - 1];
        $current_month = $current_month - 1;
    }

    // if birth month exceeds
    // current month, then do
    // not count this year and
    // add 12 to the month so
    // that we can subtract and
    // find out the difference
    if ($birth_month > $current_month)
    {
        $current_year = $current_year - 1;
        $current_month = $current_month + 12;
    }

    // calculate date, month, year
    $calculated_date = $current_date -
                       $birth_date;
    $calculated_month = $current_month -
                        $birth_month;
    $calculated_year = $current_year -
                       $birth_year;

    // print the present age
    echo "Present Age\nYears:",$calculated_year,
         " " , "Months:", $calculated_month, " ",
                       "Days:", $calculated_date;

}

    // Driver Code
    // current dd// mm/yyyy
    $current_date = 7;
    $current_month = 12;
    $current_year = 2017;

    // birth dd// mm// yyyy
    $birth_date = 16;
    $birth_month = 12;
    $birth_year = 2009;

    // function call to print age
    findAge($current_date, $current_month,
            $current_year, $birth_date,
            $birth_month, $birth_year);

// This code is contributed by anuj_67.
?>

Javascript

<script>

// Javascript program for age calculator

// function to calculate current age
function findAge(current_date, current_month, current_year, birth_date,
             birth_month, birth_year)
{
    // days of every month
    month = [31, 28, 31, 30, 31, 30, 31,
                        31, 30, 31, 30, 31 ]

    // if birth date is greater than current date
    // then do not count this month and add 30
    // to the date so as to subtract the date and
    // get the remaining days
    if (birth_date > current_date) {
        current_date = current_date + month[birth_month - 1];
        current_month = current_month - 1;
    }

    // if birth month exceeds current month, then do
    // not count this year and add 12 to the month so
    // that we can subtract and find out the difference
    if (birth_month > current_month) {
        current_year = current_year - 1;
        current_month = current_month + 12;
    }

    // calculate date, month, year
    var calculated_date = current_date - birth_date;
    var calculated_month = current_month - birth_month;
    var calculated_year = current_year - birth_year;

    // print the present age
    document.write("Present Age<br>Years: "+(calculated_year)+" ");
    document.write("Months: "+calculated_month+" ");
    document.write("Days: "+calculated_date+" ");
}

// driver code to check the above function
// current dd// mm/yyyy
var current_date = 7;
var current_month = 12;
var current_year = 2017;
// birth dd// mm// yyyy
var birth_date = 16;
var birth_month = 12;
var birth_year = 2009;
// function call to print age
findAge(current_date, current_month, current_year,
            birth_date, birth_month, birth_year);

</script>

Output

Present Age
Years: 7  Months: 11  Days: 22

Time Complexity: O(1)

Auxiliary Space: O(1)