Boost Your Coding Skills with Dart Practice Problems | Flutter

1. Dart program that generates a Fibonacci series based on user input.

import 'dart:io';

void main() {
  print("Enter the number of terms for the Fibonacci series: ");
  String input = stdin.readLineSync()!;
  int n = int.parse(input);

  if (n <= 0) {
    print("Please enter a positive integer.");
  } else {
    print("Fibonacci Series with $n terms:");
    for (int i = 0; i < n; i++) {
      print(fibonacci(i));
    }
  }
}

int fibonacci(int n) {
  if (n <= 1) {
    return n;
  } else {
    return fibonacci(n - 1) + fibonacci(n - 2);
  }
}

2. Find the minimum value in a list in Dart by first taking input from the user.

import 'dart:io';

void main() {
  // Take input from the user
  print("Enter a list of numbers separated by spaces:");
  String input = stdin.readLineSync() ?? "";
  List<String> inputList = input.split(' ');

  List<int> numbers = [];

  for (String item in inputList) {
    try {
      int number = int.parse(item);
      numbers.add(number);
    } catch (e) {
      print("Invalid input: $item is not a valid number.");
    }
  }

  if (numbers.isEmpty) {
    print("No valid numbers entered. Cannot find the minimum value.");
  } else {
    int minValue = findMinimumValue(numbers);
    print("The minimum value in the list is: $minValue");
  }
}

int findMinimumValue(List<int> numbers) {
  int minValue = numbers[0];
  for (int number in numbers) {
    if (number < minValue) {
      minValue = number;
    }
  }
  return minValue;
}

3. A Dart program that takes user input and checks if the number is an Armstrong number or not.

import 'dart:io';

void main() {
  print("Enter a number: ");
  int num = int.parse(stdin.readLineSync()!);

  int sum = 0;
  int temp = num;

  while (temp > 0) {
    int digit = temp % 10;
    sum = sum + (digit * digit * digit);
    temp ~/= 10;
  }

  if (num == sum) {
    print("$num is an Armstrong number.");
  } else {
    print("$num is not an Armstrong number.");
  }
}

4. How you can create a Factorial function in Dart that takes input from the user?

import 'dart:io';

int factorial(int n) {
  if (n == 0 || n == 1) {
    return 1;
  } else {
    return n * factorial(n - 1);
  }
}

void main() {
  stdout.write("Enter a number to find its factorial: ");
  String input = stdin.readLineSync() ?? '';
  int number = int.tryParse(input) ?? 0;

  if (number < 0) {
    print("Factorial is not defined for negative numbers.");
  } else {
    int result = factorial(number);
    print("The factorial of $number is $result");
  }
}

5. Print pattern 1 in Dart.

import 'dart:io';

void printPattern() {
  int size = 11;

  for (int i = 0; i < size; i++) {
    for (int j = 0; j < size - i; j++) {
      stdout.write('  ');
    }
    for (int k = 0; k <= i; k++) {
      int num = (k + i) % 10;
      stdout.write('$num ');
    }
    for (int l = i - 1; l >= 0; l--) {
      int num = (l + i) % 10;
      stdout.write('$num ');
    }
    stdout.write('\n');
  }

  for (int i = size -2; i >= 0; i--) {
    for (int j = 0; j < size - i; j++) {
      stdout.write('  ');
    }
    for (int k = 0; k <= i; k++) {
      int num = (k + i) % 10;
      stdout.write('$num ');
    }
    for (int l = i - 1; l >= 0; l--) {
      int num = (l + i) % 10;
      stdout.write('$num ');
    }
    stdout.write('\n');
  }
}

void main() {
  printPattern();
}

6. Write a Dart program which accepts a sequence of comma-separated numbers from the user and generates a list and a tuple with those numbers.

Sample data : 3, 5, 7, 23

Output : List : [‘3’, ‘ 5’, ‘ 7’, ‘ 23’] Set : (‘3’, ‘ 5’, ‘ 7’, ‘ 23’)

import 'dart:io';

void main() {
  print("Enter a sequence of comma-separated numbers:");
  String input = stdin.readLineSync() ?? '';

  List<String> numbersList = input.split(',').map((number) => number.trim()).toList();
  var numbersTuple = Tuple.fromList(numbersList);

  print("List : $numbersList");
  print("Tuple : $numbersTuple");
}

class Tuple {
  final List<String> items;

  Tuple(this.items);

  factory Tuple.fromList(List<String> list) {
    return Tuple(List<String>.from(list));
  }

  @override
  String toString() {
    return '(${items.join(', ')})';
  }
}

7. Write a Dart program to print the calendar of a given month and year.

import 'dart:io';

void main() {
  print("Enter the year (e.g., 2023): ");
  int year = int.tryParse(stdin.readLineSync()!) ?? DateTime.now().year;

  print("Enter the month (1-12): ");
  int month = int.tryParse(stdin.readLineSync()!) ?? DateTime.now().month;

  final date = DateTime(year, month, 1);
  final lastDay = DateTime(year, month + 1, 0);
  final firstWeekday = date.weekday;

  printCalendar(month, year, firstWeekday, lastDay.day);
}

void printCalendar(int month, int year, int firstWeekday, int lastDay) {
  final monthNames = [
    'January', 'February', 'March', 'April', 'May', 'June',
    'July', 'August', 'September', 'October', 'November', 'December'
  ];

  print('${monthNames[month - 1]} $year');

  print('Su Mo Tu We Th Fr Sa');

  // Print leading spaces for the first week
  for (int i = 0; i < firstWeekday; i++) {
    stdout.write('   ');
  }

  for (int day = 1; day <= lastDay; day++) {
    if (day < 10) {
      stdout.write(' ');
    }
    stdout.write('$day ');

    if ((day + firstWeekday) % 7 == 0 || day == lastDay) {
      print('');
    }
  }
}

8. Write a Dart program to calculate number of days between two dates.

Sample dates : (2014, 7, 2), (2014, 7, 11)

Expected output : 9 days

import 'dart:io';

void main() {
  print("Enter the first date (YYYY-MM-DD): ");
  String dateStr1 = stdin.readLineSync() ?? "";

  print("Enter the second date (YYYY-MM-DD): ");
  String dateStr2 = stdin.readLineSync() ?? "";

  try {
    DateTime date1 = DateTime.parse(dateStr1);
    DateTime date2 = DateTime.parse(dateStr2);

    // Calculate the difference in days
    int differenceInDays = date2.difference(date1).inDays;

    print("Number of days between the two dates: $differenceInDays");
  } catch (e) {
    print("Invalid date format. Please enter dates in the format 'YYYY-MM-DD'.");
  }
}

9. Write a Dart program to count the number 4 in a given list (Take input from the user).

import 'dart:io';

void main() {
  print("Enter a list of numbers separated by spaces:");
  String input = stdin.readLineSync() ?? '';
  
  List<String> numbers = input.split(' ');

  int countOfFour = countNumberFour(numbers);
  print("The number 4 occurs $countOfFour time(s) in the list.");
}

int countNumberFour(List<String> numbers) {
  int count = 0;
  for (var number in numbers) {
    if (number.contains('4')) {
      for (var digit in number.runes) {
        if (String.fromCharCode(digit) == '4') {
          count++;
        }
      }
    }
  }
  return count;
}

10. Dart program that performs all the basic arithmetic operations (+ addition, — subtraction, * multiplication, / division) on two numbers provided by the user.

import 'dart:io';

void main() {
  print("Enter two numbers:");
  double? num1 = double.tryParse(stdin.readLineSync()!);
  double? num2 = double.tryParse(stdin.readLineSync()!);

  if (num1 != null && num2 != null) {
    print("Addition: ${num1 + num2}");
    print("Subtraction: ${num1 - num2}");
    print("Multiplication: ${num1 * num2}");
    if (num2 != 0) {
      print("Division: ${num1 / num2}");
    } else {
      print("Division by zero is not possible.");
    }
  } else {
    print("Invalid input. Please enter valid numbers.");
  }
}

11. Dart program that converts feet to meters.

import 'dart:io';

void main() {
  print("Enter the length in feet:");
  double? feet = double.tryParse(stdin.readLineSync()!);

  if (feet != null) {
    double meters = feet * 0.3048; // 1 foot is equal to 0.3048 meters
    print("$feet feet is equal to $meters meters.");
  } else {
    print("Invalid input. Please enter a valid number for feet.");
  }
}

12. Dart program that converts Celsius to Fahrenheit.

import 'dart:io';

void main() {
  print("Enter the temperature in Celsius:");
  double? celsius = double.tryParse(stdin.readLineSync()!);

  if (celsius != null) {
    double fahrenheit = (celsius * 9 / 5) + 32; // Formula to convert Celsius to Fahrenheit
    print("$celsius°C is equal to $fahrenheit°F.");
  } else {
    print("Invalid input. Please enter a valid temperature in Celsius.");
  }
}

13. Dart program that converts Fahrenheit to Celsius.

import 'dart:io';

void main() {
  print("Enter the temperature in Fahrenheit:");
  double? fahrenheit = double.tryParse(stdin.readLineSync()!);

  if (fahrenheit != null) {
    double celsius = (fahrenheit - 32) * (5 / 9); // Formula to convert Fahrenheit to Celsius
    print("$fahrenheit°F is equal to $celsius°C.");
  } else {
    print("Invalid input. Please enter a valid temperature in Fahrenheit.");
  }
}

14. Dart program that reverses a string entered by the user.

import 'dart:io';

void main() {
  print("Enter a string:");
  String? input = stdin.readLineSync();

  if (input != null) {
    String reversedString = reverseString(input);
    print("Reversed string: $reversedString");
  } else {
    print("No input provided. Please enter a string.");
  }
}

String reverseString(String input) {
  String reversed = input.split('').reversed.join();
  return reversed;
}

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15. Dart program that counts the number of alphabets, digits, and special characters in a string entered by the user.

import 'dart:io';

void main() {
  print("Enter a string:");
  String? input = stdin.readLineSync();

  if (input != null) {
    Map<String, int> characterCount = countCharacters(input);
    print("Number of alphabets: ${characterCount['alphabets']}");
    print("Number of digits: ${characterCount['digits']}");
    print("Number of special characters: ${characterCount['special']}");
  } else {
    print("No input provided. Please enter a string.");
  }
}

Map<String, int> countCharacters(String input) {
  int alphabets = RegExp(r'[a-zA-Z]').allMatches(input).length;
  int digits = RegExp(r'\d').allMatches(input).length;
  int special = input.length - alphabets - digits;

  return {'alphabets': alphabets, 'digits': digits, 'special': special};
}

16. Dart program that swaps the first and last digit of a number provided by the user.

import 'dart:io';

void main() {
  print("Enter a number:");
  String input = stdin.readLineSync() ?? '';

  if (input.isNotEmpty) {
    int number = int.parse(input);
    int swappedNumber = swapFirstLastDigit(number);

    print("Number after swapping first and last digit: $swappedNumber");
  } else {
    print("Invalid input. Please enter a number.");
  }
}

int swapFirstLastDigit(int number) {
  if (number < 10) {
    return number;
  } else {
    int lastDigit = number % 10;
    int firstDigit = int.parse(number.toString()[0]);
    int power = 1;
    int temp = number;

    while (temp >= 10) {
      temp ~/= 10;
      power *= 10;
    }
c    
    // Formula to swap first and last digits
    int newNumber = lastDigit * power;
    newNumber += number % power;
    newNumber -= lastDigit;
    newNumber += firstDigit;

    return newNumber;
  }
}

17. How to measure the execution time for a Dart method?

void main() {
  // Call the method and measure its execution time
  measureExecutionTime(myMethod);
}

void myMethod() {
  // Example method that you want to measure the execution time
  for (int i = 0; i < 100000000; i++) {
    // Some computation or task
  }
}

void measureExecutionTime(Function method) {
  var stopwatch = Stopwatch()..start();
  method(); // Call the method
  stopwatch.stop();

  print('Execution time: ${stopwatch.elapsed}');
}

18. Write a Dart program to get OS name, platform and release information.

import 'dart:io';

void main() {
  print("OS Name: ${Platform.operatingSystem}");
  print("OS Version: ${Platform.operatingSystemVersion}");
  print("OS Platform: ${Platform.operatingSystem}");
  print("OS Architecture: ${Platform.operatingSystem}");
  print("Dart VM: ${Platform.version}");
}

19. Write a Dart program to get the number of processors.

import 'dart:io';

void main() {
  int processors = Platform.numberOfProcessors;
  print('Number of Processors: $processors');
}

20. Dart program that checks whether a number is a palindrome or not.

import 'dart:io';

void main() {
  print("Enter a number to check if it's a palindrome: ");
  int number = int.parse(stdin.readLineSync() ?? '0');

  bool isPalindrome = checkPalindrome(number);

  if (isPalindrome) {
    print("$number is a palindrome number.");
  } else {
    print("$number is not a palindrome number.");
  }
}

bool checkPalindrome(int number) {
  int reversedNumber = 0;
  int originalNumber = number;

  while (number > 0) {
    int remainder = number % 10;
    reversedNumber = reversedNumber * 10 + remainder;
    number = number ~/ 10;
  }

  return originalNumber == reversedNumber;
}

21. Dart program that converts a decimal number entered by the user into its equivalent binary number.

import 'dart:io';

void main() {
  print("Enter a decimal number to convert to binary: ");
  int decimalNumber = int.parse(stdin.readLineSync() ?? '0');

  String binaryNumber = convertToBinary(decimalNumber);
  print("Binary representation: $binaryNumber");
}

String convertToBinary(int decimalNumber) {
  return decimalNumber.toRadixString(2);
}

22. Dart program that converts a binary number entered by the user into its decimal number.

import 'dart:io';

void main() {
  print("Enter a binary number: ");
  String binary = stdin.readLineSync() ?? '0';

  int decimal = binaryToDecimal(binary);

  print("Decimal equivalent: $decimal");
}

int binaryToDecimal(String binary) {
  int decimal = 0;
  int power = 0;

  for (int i = binary.length - 1; i >= 0; i--) {
    int digit = int.parse(binary[i]);
    decimal += digit * (1 << power);
    power++;
  }

  return decimal;
}

23. Dart program that calculates the Least Common Multiple (LCM) of two numbers provided by the user.

import 'dart:io';

void main() {
  print("Enter first number: ");
  int num1 = int.parse(stdin.readLineSync() ?? '0');

  print("Enter second number: ");
  int num2 = int.parse(stdin.readLineSync() ?? '0');

  int lcm = calculateLCM(num1, num2);

  print("The LCM of $num1 and $num2 is: $lcm");
}

int calculateLCM(int a, int b) {
  int max = (a > b) ? a : b;
  int step = max;

  while (true) {
    if (max % a == 0 && max % b == 0) {
      return max;
    }
    max += step;
  }
}

24. Dart program that calculates the Highest Common Factor (HCF) of two numbers provided by the user.

import 'dart:io';

void main() {
  print("Enter first number: ");
  int num1 = int.parse(stdin.readLineSync() ?? '0');

  print("Enter second number: ");
  int num2 = int.parse(stdin.readLineSync() ?? '0');

  int hcf = calculateHCF(num1, num2);

  print("The HCF of $num1 and $num2 is: $hcf");
}

int calculateHCF(int a, int b) {
  while (b != 0) {
    int remainder = a % b;
    a = b;
    b = remainder;
  }
  return a;
}

25. Dart program that converts a number (up to 999) to its corresponding words.

import 'dart:io';

void main() {
  print("Enter a number (up to 999): ");
  int number = int.parse(stdin.readLineSync() ?? '0');

  String words = numberToWords(number);

  print("Number in words: $words");
}

String numberToWords(int number) {
  List<String> units = [
    '', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine'
  ];
  List<String> teens = [
    'ten', 'eleven', 'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen'
  ];
  List<String> tens = [
    '', '', 'twenty', 'thirty', 'forty', 'fifty', 'sixty', 'seventy', 'eighty', 'ninety'
  ];

  if (number == 0) {
    return 'zero';
  }

  String words = '';
  if (number >= 100) {
    words += units[number ~/ 100] + ' hundred ';
    number %= 100;
  }

  if (number >= 10 && number < 20) {
    words += teens[number - 10];
  } else {
    words += tens[number ~/ 10] + ' ' + units[number % 10];
  }

  return words.trim();
}

26. Dart program to determine whether a number entered by the user is a prime number.

import 'dart:io';

void main() {
  print("Enter a number: ");
  int number = int.parse(stdin.readLineSync() ?? '0');

  if (isPrime(number)) {
    print("$number is a prime number.");
  } else {
    print("$number is not a prime number.");
  }
}

bool isPrime(int number) {
  if (number <= 1) {
    return false;
  }

  for (int i = 2; i <= number / 2; i++) {
    if (number % i == 0) {
      return false;
    }
  }
  return true;
}