Programming Technique 2014/2015 Semester 1 Labsheet 4

Calculate age

/*--------------------------------------------------------------------
 | TITLE: Calculate age
 +--------------------------------------------------------------------
 |       AUTHOR: Nik Mohamad Aizuddin b. Nik Azmi
 |        EMAIL: nickaizuddin93@gmail.com
 | DATE CREATED: 12/NOV/2014
 |      PURPOSE: My answer for the subject Programming Technique
 |               2014/2015 Semester 1 Labsheet 4.
 +--------------------------------------------------------------------
 | LANGUAGE: C
 | STANDARD: C89-Strict
 +--------------------------------------------------------------------
 | VERSION HISTORY:
 |
 |  Version |     Date    |                 Description
 | ---------+-------------+------------------------------------------
 |    1.0.0 | 12/NOV/2014 | First released.
 |
 +--------------------------------------------------------------------
 | PROGRAM'S LIMITATIONS:
 |   --> The program doesn't to check for date validity. Assume you 
 |       always insert valid date.
 |   --> Assume that end date is more latest compared to start date.
 +------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h> /** for strcpy() use */

/************************ get_birth_date() ***************************
 * Get user birth date.
 *
 *     @param1: pBirth_day   = address to birth_day variable
 *     @param2: pBirth_month = address to birth_month variable
 *     @param3: pBirth_year  = address to birth_year variable
 *
 *     @return: nothing
 */
void get_birth_date(int *pBirth_day,
                    int *pBirth_month,
                    int *pBirth_year)
{
    int birth_day   = 0;
    int birth_month = 0;
    int birth_year  = 0;

    /** Tell user to enter their birth date and get the input */

    printf("Insert birth year [for example: 1993]: ");
    scanf(" %d", &birth_year);

    printf("Insert birth month [for example: 10]: ");
    scanf(" %d", &birth_month);

    printf("Insert birth day [for example: 29]: ");
    scanf(" %d", &birth_day);

    /**
     * Pass the birth_day value to the variable
     * at address pBirth_day
     */
    *pBirth_day = birth_day;

    /**
     * Pass the birth_month value to the variable
     * at address pBirth_month
     */
    *pBirth_month = birth_month;

    /**
     * Pass the birth_year value to the variable
     * at address pBirth_year
     */
    *pBirth_year = birth_year;
}

/*********************** get_current_date() **************************
 * Get current date
 *
 *     @param1: pCurrent_day   = address to current_day variable
 *     @param2: pCurrent_month = address to current_month variable
 *     @param3: pCurrent_year  = address to current_year variable
 *
 *     @return:
 */
void get_current_date(int *pCurrent_day,
                      int *pCurrent_month,
                      int *pCurrent_year)
{
    int current_day   = 0;
    int current_month = 0;
    int current_year  = 0;

    /** Tell user to enter current date and get the input */

    printf("Insert current year [for example: 2014]: ");
    scanf(" %d", &current_year);

    printf("Insert current month [for example: 11]: ");
    scanf(" %d", &current_month);

    printf("Insert current day [for example: 12]: ");
    scanf(" %d", &current_day);

    /**
     * Pass the current_day value to the variable
     * at address pCurrent_day
     */
    *pCurrent_day = current_day;

    /**
     * Pass the current_month value to the variable
     * at address pCurrent_month
     */
    *pCurrent_month = current_month;

    /**
     * Pass the current_year value to the variable
     * at address pCurrent_year
     */
    *pCurrent_year = current_year;
}

/************************ calculate_age() ***************************
 * Calculate age at specified date
 *
 *     @param1: birth_day     = day of birth
 *     @param2: birth_month   = month of birth
 *     @param3: birth_year    = year of birth
 *     @param4: current_day   = current day
 *     @param5: current_month = current month
 *     @param6: current_year  = current year
 *     @param7: pAge_day      = address to variable age_day
 *     @param8: pAge_month    = address to variable age_month
 *     @param9: pAge_year     = address to variable age_year
 *
 *     @return: nothing
 */
void calculate_age(int birth_day,
                   int birth_month,
                   int birth_year,
                   int current_day,
                   int current_month,
                   int current_year,
                   int *pAge_day,
                   int *pAge_month,
                   int *pAge_year)
{
    int age_day   = 0;
    int age_month = 0;
    int age_year  = 0;

    /** Find the difference in year */
    age_year = current_year - birth_year;

    /**
     * If current_month < birth_month,
     * decrement age_year and add 12 to current_month
     */
    if(current_month < birth_month) {
        age_year = age_year - 1;
        current_month = current_month + 12;
    }

    /** Find the differences in month */
    age_month = current_month - birth_month;

    /**
     * If current_day < birth_day,
     * decrement age_month and add 31 to current_day
     */
    if(current_day < birth_day) {
        age_month = age_month - 1;
        current_day = current_day + 31;
    }

    /** Find differences in day */
    age_day = current_day - birth_day;

    /**
     * Pass value age_day to variable
     * address at pAge_day
     */
    *pAge_day = age_day;

    /**
     * Pass value age_month to variable
     * address at pAge_month
     */
    *pAge_month = age_month;

    /**
     * Pass value age_year to variable
     * address at pAge_year
     */
    *pAge_year = age_year;
}

/*************************** print_age() *****************************
 * Print age at 31 December and at specifed date
 *
 *     @param1: current_day
 *     @param2: current_month
 *     @param3: current_year
 *     @param4: age_31dec2009_day
 *     @param5: age_31dec2009_month
 *     @param6: age_31dec2009_year
 *     @param7: age_current_day
 *     @param8: age_current_month
 *     @param9: age_current_year
 *
 *     @return: nothing
 */
void print_age(int current_day,
               int current_month,
               int current_year,
               int age_31dec2009_day,
               int age_31dec2009_month,
               int age_31dec2009_year,
               int age_current_day,
               int age_current_month,
               int age_current_year)
{
    char str_current_month[16];

    /** Print age at 31 December 2009 */

    printf(
    "Your age as 31 December 2009 is %d years %d months %d days\n",
        age_31dec2009_year, age_31dec2009_month, age_31dec2009_day);

    /** Print age at current date */

    switch(current_month) {
        case 1:
            strcpy(str_current_month, "January");
            break;
        case 2:
            strcpy(str_current_month, "February");
            break;
        case 3:
            strcpy(str_current_month, "March");
            break;
        case 4:
            strcpy(str_current_month, "April");
            break;
        case 5:
            strcpy(str_current_month, "May");
            break;
        case 6:
            strcpy(str_current_month, "Jun");
            break;
        case 7:
            strcpy(str_current_month, "July");
            break;
        case 8:
            strcpy(str_current_month, "August");
            break;
        case 9:
            strcpy(str_current_month, "September");
            break;
        case 10:
            strcpy(str_current_month, "October");
            break;
        case 11:
            strcpy(str_current_month, "November");
            break;
        case 12:
            strcpy(str_current_month, "December");
            break;
        default:
            break;
    }

    printf(
    "Your age as %d %s %d is %d years %d months %d days\n",
        current_day, str_current_month, current_year,
        age_current_year, age_current_month, age_current_day);
}

int main(void)
{
    int birth_day   = 0;
    int birth_month = 0;
    int birth_year  = 0;

    int current_day   = 0;
    int current_month = 0;
    int current_year  = 0;

    int age_31dec2009_day   = 0;
    int age_31dec2009_month = 0;
    int age_31dec2009_year  = 0;

    int age_current_day   = 0;
    int age_current_month = 0;
    int age_current_year  = 0;

    /** Get birth date and current date */
    get_birth_date(&birth_day, &birth_month, &birth_year);
    get_current_date(&current_day, &current_month, &current_year);

    /** Calculate age at 31 December 2009 */
    calculate_age(birth_day,
                  birth_month,
                  birth_year,
                  31,
                  12,
                  2009,
                  &age_31dec2009_day,
                  &age_31dec2009_month,
                  &age_31dec2009_year);

    /** Calculate age at specified date (current_date) */
    calculate_age(birth_day,
                  birth_month,
                  birth_year,
                  current_day,
                  current_month,
                  current_year,
                  &age_current_day,
                  &age_current_month,
                  &age_current_year);

    /** Display age at 31 December 2009 and at specified date */
    print_age(current_day,
              current_month,
              current_year,
              age_31dec2009_day,
              age_31dec2009_month,
              age_31dec2009_year,
              age_current_day,
              age_current_month,
              age_current_year);

    return 0;
}