**Course Title:** Mastering Dart: From Fundamentals to Flutter Development **Section Title:** Introduction to Dart and Development Environment **Topic:** Basic Dart syntax: variables, data types, and operators In the previous topic, we set up our Dart development environment and explored the basics of the Dart SDK and IDEs. Now, it's time to dive into the core syntax of the Dart programming language. This topic will cover the fundamental building blocks of Dart programming, including variables, data types, and operators. By the end of this topic, you'll have a solid understanding of the basic syntax and be able to write your first Dart programs. ### Variables in Dart In Dart, a variable is a name given to a storage location that holds a value. You can think of a variable as a labeled box where you can store a value. To declare a variable in Dart, you use the `var` keyword followed by the name of the variable. For example: ```dart var name = 'John Doe'; ``` In this example, `name` is the variable name, and `'John Doe'` is the value assigned to it. You can also declare a variable without assigning a value to it: ```dart var name; ``` In this case, the variable `name` is declared but not initialized. Dart also supports type inference, which means you can declare a variable without specifying its type. For example: ```dart var age = 25; ``` In this case, Dart infers that the type of the variable `age` is `int`. However, it's a good practice to specify the type of the variable explicitly: ```dart int age = 25; ``` This approach provides more clarity and helps avoid bugs. ### Data Types in Dart Dart supports the following basic data types: 1. **Numbers**: `int` and `double` * `int`: whole numbers, such as 1, 2, 3, etc. * `double`: decimal numbers, such as 3.14, -0.5, etc. 2. **Strings**: sequences of characters, such as 'hello', "hello", etc. 3. **Booleans**: true or false values 4. **Lists**: ordered collections of values, such as [1, 2, 3] 5. **Maps**: unordered collections of key-value pairs, such as {'name': 'John', 'age': 25} Here's an example of declaring variables with different data types: ```dart int age = 25; double height = 1.75; String name = 'John Doe'; bool isAdmin = true; List<int> numbers = [1, 2, 3]; Map<String, int> scores = {'John': 90, 'Jane': 85}; ``` ### Operators in Dart Dart supports a variety of operators for performing arithmetic, comparison, logical, and assignment operations. **Arithmetic Operators** * `+` (addition) * `-` (subtraction) * `*` (multiplication) * `/` (division) * `%` (modulus) * `~/` (integer division) Example: ```dart int a = 5; int b = 3; print(a + b); // prints 8 print(a - b); // prints 2 print(a * b); // prints 15 print(a / b); // prints 1.6666666666666667 ``` **Comparison Operators** * `==` (equality) * `!=` (inequality) * `>` (greater than) * `<` (less than) * `>=` (greater than or equal to) * `<=` (less than or equal to) Example: ```dart int a = 5; int b = 3; print(a == b); // prints false print(a != b); // prints true print(a > b); // prints true ``` **Logical Operators** * `&&` (and) * `||` (or) * `!` (not) Example: ```dart bool isAdmin = true; bool isOwner = false; print(isAdmin && isOwner); // prints false print(isAdmin || isOwner); // prints true print(!isAdmin); // prints false ``` **Assignment Operators** * `=` (assignment) * `+=` (addition assignment) * `-=` (subtraction assignment) * `*=` (multiplication assignment) * `/=` (division assignment) * `%=` (modulus assignment) Example: ```dart int a = 5; a += 3; print(a); // prints 8 ``` ### Conclusion In this topic, we covered the basic syntax of the Dart programming language, including variables, data types, and operators. You now know how to declare variables, specify their types, and perform various operations using operators. To reinforce your understanding, try the following exercises: 1. Declare a variable `name` and assign it a string value. Then, use the `==` operator to compare it with another string. 2. Use the `+` operator to add two numbers and assign the result to a variable. 3. Use the `&&` operator to combine two boolean values and print the result. **What's Next?** In the next topic, we'll cover control structures, including conditional statements and loops. You'll learn how to write more complex programs that can make decisions and repeat tasks. **Leave a Comment/Ask for Help** If you have any questions or need help with any of the concepts covered in this topic, feel free to leave a comment below. **External Links** * [Dart Language Tour](https://dart.dev/guides/language/language-tour) * [Dart Variables](https://dart.dev/guides/language/language-tour#variables) * [Dart Data Types](https://dart.dev/guides/language/language-tour#built-in-types)