1. Dart
  2. Dart Basics
  3. Dart Basics Practice Programs with Solutions
  1. You are developing a simple application for a library. Declare a variable named numberOfBooks of type int and assign it the total number of books in the library, which is 1500. Print the number of books.
  2. In a weather application, declare a variable temperature of type double to represent the current temperature in Celsius. Assign it a value of 23.5 and print the temperature.
  3. Write a Dart program that calculates the area of a rectangle. Add comments to explain each part of the code, including variable declarations and calculations.
  4. In a shopping cart application, declare two variables itemPrice and quantity. Assign them values of 20.0 and 3, respectively. Calculate the total cost and print it.
  5. Create a program that asks the user for their name and age. Print a greeting message that includes their name and the year they were born.
  6. In a social media application, declare a variable username and assign it your chosen username. Print a message that includes the username and its length.
  7. Write a program that declares a bool variable named isMember to indicate if a user is a member of a gym. Assign it true and print a message stating whether the user is a member or not.
  8. Create a Dart program that declares a variable price of type num to represent the price of an item. Assign it a value of 99.99 and print the price.
  9. Write a Dart program that converts kilometers to miles. Include comments explaining the conversion formula and the output.

  10. In a recipe application, declare a variable sugarCups and assign it a value of 2.5. Calculate the total amount of sugar needed for 4 servings and print the result.


    1. Understanding Variables in Dart

Question: You are developing a simple application for a library. Declare a variable named numberOfBooks of type int and assign it the total number of books in the library, which is 1500. Print the number of books.

Solution:

void main() {
  int numberOfBooks = 1500; // Declare and initialize the variable   print('Number of books in the library: $numberOfBooks'); // Print the value }

Explanation:

  • int numberOfBooks = 1500;: This line declares an integer variable named numberOfBooks and assigns it a value of 1500, representing the total number of books in the library.
  • print('Number of books in the library: $numberOfBooks');: This line uses string interpolation to format the output string, which includes the variable value.

2. Exploring Data Types in Dart

Question: In a weather application, declare a variable temperature of type double to represent the current temperature in Celsius. Assign it a value of 23.5 and print the temperature.

Solution:

void main() {
  double temperature = 23.5; // Declare and initialize the variable   print('Current temperature: $temperature °C'); // Print the temperature }

Explanation:

  • double temperature = 23.5;: This line declares a variable temperature of type double and assigns it the value 23.5, indicating the current temperature in Celsius.
  • print('Current temperature: $temperature °C');: This line prints the current temperature, using string interpolation to include the variable value.

3. Adding Comments in Dart Code

Question: Write a Dart program that calculates the area of a rectangle. Add comments to explain each part of the code, including variable declarations and calculations.

Solution:

void main() {
  // Declare the length and width of the rectangle   double length = 5.0; // Length in units   double width = 3.0;  // Width in units 
  // Calculate the area of the rectangle   double area = length * width; // Area = length * width 
  // Print the area   print('Area of the rectangle: $area square units');
}

Explanation:

  • The program starts by declaring variables length and width to represent the dimensions of the rectangle.
  • The area is calculated by multiplying length and width, and the result is stored in the area variable.
  • Finally, the program prints the calculated area, with comments explaining each step.

4. Working with Operators in Dart

Question: In a shopping cart application, declare two variables itemPrice and quantity. Assign them values of 20.0 and 3, respectively. Calculate the total cost and print it.

Solution:

void main() {
  double itemPrice = 20.0; // Price of a single item   int quantity = 3;        // Number of items 
  // Calculate total cost   double totalCost = itemPrice * quantity;

  // Print total cost   print('Total cost: \$${totalCost}');
}

Explanation:

  • double itemPrice = 20.0;: This line declares a variable itemPrice to represent the price of a single item.
  • int quantity = 3;: This line declares a variable quantity to represent how many items are being purchased.
  • The total cost is calculated by multiplying itemPrice and quantity, and the result is stored in totalCost.
  • The program prints the total cost, formatting it as currency.

5. Getting User Input in Dart

Question: Create a program that asks the user for their name and age. Print a greeting message that includes their name and the year they were born.

Solution:

import 'dart:io'; // Import the dart:io library for input 
void main() {
  // Prompt for user input   stdout.write('Enter your name: ');
  String? name = stdin.readLineSync(); // Read the name from user input 
  stdout.write('Enter your age: ');
  String? ageInput = stdin.readLineSync(); // Read the age from user input   int age = int.parse(ageInput!); // Convert age to an integer 
  // Calculate the year of birth   int yearBorn = DateTime.now().year - age;

  // Print the greeting message   print('Hello, $name! You were born in $yearBorn.');
}

Explanation:

  • The program imports the dart:io library to read user input from the console.
  • It prompts the user for their name and age, reading these values using stdin.readLineSync().
  • The age string is converted to an integer using int.parse().
  • The year of birth is calculated by subtracting the age from the current year.
  • Finally, the program prints a greeting message that includes the user's name and calculated year of birth.

6. Manipulating Strings in Dart

Question: In a social media application, declare a variable username and assign it your chosen username. Print a message that includes the username and its length.

Solution:

void main() {
  String username = 'DartFan'; // Declare and initialize username   int usernameLength = username.length; // Get the length of the username 
  // Print the username and its length   print('Username: $username, Length: $usernameLength characters');
}

Explanation:

  • String username = 'DartFan';: This line declares a variable username and assigns it a string value.
  • int usernameLength = username.length;: The length property is used to get the number of characters in the username.
  • The program prints the username and its length using string interpolation.

7. Understanding Variables in Dart

Question: Write a program that declares a bool variable named isMember to indicate if a user is a member of a gym. Assign it true and print a message stating whether the user is a member or not.

Solution:

void main() {
  bool isMember = true; // Declare a boolean variable 
  // Print membership status   if (isMember) {
    print('You are a gym member.');
  } else {
    print('You are not a gym member.');
  }
}

Explanation:

  • bool isMember = true;: This line declares a boolean variable isMember to indicate membership status.
  • The program uses an if statement to check the value of isMember and prints an appropriate message based on whether the user is a member or not.

8. Exploring Data Types in Dart

Question: Create a Dart program that declares a variable price of type num to represent the price of an item. Assign it a value of 99.99 and print the price.

Solution:

void main() {
  num price = 99.99; // Declare a variable of type num 
  // Print the price   print('The price of the item is: \$${price}');
}

Explanation:

  • num price = 99.99;: This line declares a variable price of type num, which can hold both integers and doubles.
  • The program prints the price using string interpolation to format it as currency.

9. Adding Comments in Dart Code

Question: Write a Dart program that converts kilometers to miles. Include comments explaining the conversion formula and the output.

Solution:

void main() {
  // Declare the distance in kilometers   double kilometers = 10.0;

  // Conversion factor from kilometers to miles   double conversionFactor = 0.621371;

  // Calculate the distance in miles   double miles = kilometers * conversionFactor;

  // Print the result   print('$kilometers kilometers is equal to $miles miles.');
}

Explanation:

  • The program declares a variable kilometers to hold the distance in kilometers.
  • A conversion factor is defined to convert kilometers to miles.
  • The distance in miles is calculated by multiplying kilometers by conversionFactor.
  • Finally, the program prints the result, including both kilometers and miles.

10. Working with Operators in Dart

Question: In a recipe application, declare a variable sugarCups and assign it a value of 2.5. Calculate the total amount of sugar needed for 4 servings and print the result.

Solution:

void main() {
  double sugarCups = 2.5; // Amount of sugar for one serving 
  // Calculate total sugar for 4 servings   double totalSugar = sugarCups * 4;

  // Print the total amount of sugar needed   print('Total sugar needed for 4 servings: $totalSugar cups');
}

Explanation:

  • double sugarCups = 2.5;: This line declares a variable sugarCups, which represents the amount of sugar needed for one serving.
  • The total amount of sugar for 4 servings is calculated by multiplying sugarCups by 4.
  • Finally, the program prints the total amount of sugar needed, formatted for clarity.
Previous
Next