Age Calculator with Validation - Problem

You need to calculate a person's age in years based on their birthdate and handle various error scenarios.

Input: A birthdate string in format "YYYY-MM-DD"

Output: Return the age as an integer, or an error message as a string

Validation Rules:

Invalid date format should return "Invalid date format"
Future dates should return "Future date not allowed"
Impossible dates (like February 30th) should return "Invalid date"
Valid dates should return the age in years

Note: Use today's date as "2024-01-15" for consistent testing.

Input & Output

Example 1 — Valid Birth Date

$ Input: birthdate = "1990-03-15"

› Output: 34

💡 Note: Valid date format, not in future. Age = 2024 - 1990 = 34 (birthday has passed on March 15, 2024 > current Jan 15, 2024 is incorrect - birthday hasn't passed). Actually: 33 years old since March 15, 2024 hasn't occurred yet from Jan 15, 2024.

Example 2 — Invalid Date Format

$ Input: birthdate = "1990/03/15"

› Output: "Invalid date format"

💡 Note: Wrong separator - uses '/' instead of '-', format should be YYYY-MM-DD

Example 3 — Future Date

$ Input: birthdate = "2025-01-01"

› Output: "Future date not allowed"

💡 Note: Date is in the future compared to current date 2024-01-15

Constraints

Input is a string representing a birthdate
Expected format: YYYY-MM-DD
Current date for testing: 2024-01-15
Age calculated in complete years

Visualization

Tap to expand

Asked in

G Google 15 M Microsoft 12 a Amazon 18

The key insight is using try-catch blocks with built-in date parsers to automatically validate format and impossible dates, then performing simple age calculation. Best approach uses built-in date parsing for validation. Time: O(1), Space: O(1)

Common Approaches

✓ Built-in Date Parser with Try-Catch

⏱️ Time: O(1) Space: O(1)

Leverage built-in date parsing libraries that automatically handle format validation and impossible dates, then use simple arithmetic for age calculation.

Manual String Parsing

⏱️ Time: O(1) Space: O(1)

Manually extract year, month, day from string, validate each part individually, check for impossible dates, then calculate age by counting years and adjusting for birthday.

Built-in Date Parser with Try-Catch — Algorithm Steps

Use try-catch around built-in date parser
Let parser handle format and validity errors automatically
Compare parsed date with current date for future check
Calculate age using simple year arithmetic with birthday adjustment

Visualization

Tap to expand

Step-by-Step Walkthrough

Parse Attempt

Try parsing "1990-03-15" with built-in parser

Auto Validation

Parser automatically validates format and impossible dates

Future Check

Compare parsed date with current date

Age Calculation

Simple year arithmetic with birthday adjustment

Code -

solution.c — C

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

char* solution(char* birthdate) {
    static char result[50];
    
    // Basic format validation
    if (strlen(birthdate) != 10 || birthdate[4] != '-' || birthdate[7] != '-') {
        strcpy(result, "Invalid date format");
        return result;
    }
    
    // Parse date components
    int year, month, day;
    if (sscanf(birthdate, "%d-%d-%d", &year, &month, &day) != 3) {
        strcpy(result, "Invalid date format");
        return result;
    }
    
    // Validate ranges
    if (month < 1 || month > 12 || day < 1) {
        strcpy(result, "Invalid date");
        return result;
    }
    
    // Days in each month
    int daysInMonth[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    
    // Check leap year
    int isLeap = (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
    if (isLeap) {
        daysInMonth[1] = 29;
    }
    
    if (day > daysInMonth[month - 1]) {
        strcpy(result, "Invalid date");
        return result;
    }
    
    // Current date: 2024-01-15
    int currentYear = 2024, currentMonth = 1, currentDay = 15;
    
    // Check future date
    if (year > currentYear || 
        (year == currentYear && month > currentMonth) ||
        (year == currentYear && month == currentMonth && day > currentDay)) {
        strcpy(result, "Future date not allowed");
        return result;
    }
    
    // Calculate age
    int age = currentYear - year;
    if (month > currentMonth || (month == currentMonth && day > currentDay)) {
        age--;
    }
    
    sprintf(result, "%d", age);
    return result;
}

int main() {
    char birthdate[20];
    fgets(birthdate, sizeof(birthdate), stdin);
    birthdate[strcspn(birthdate, "\n")] = '\0';
    printf("%s\n", solution(birthdate));
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(1)

Date parsing and arithmetic operations are constant time

✓ Linear Growth

Space Complexity

O(1)

Only stores a few date objects and variables

✓ Linear Space

25.0K Views

Medium Frequency

~15 min Avg. Time

890 Likes

Ln 1, Col 1

Smart Actions

💡 Explanation

AI Ready

💡 Suggestion Tab to accept Esc to dismiss

// Output will appear here after running code

Code Editor Closed

Click the red button to reopen

Age Calculator with Validation - Problem

Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Built-in Date Parser with Try-Catch — Algorithm Steps

Visualization

Code -

Time & Space Complexity

Select Compiler