Dart Data Types Explained

1. int (Integer)

int is used to store whole numbers (positive or negative) without decimals.

int age = 25;
print(age);

2. double

double is used to store numbers with decimal points.

double pi = 3.14;
print(pi);

3. String

String is used to store text or a sequence of characters enclosed in quotes.

String name = "Sumit";
print(name);

4. bool (Boolean)

bool is used to store true or false values (yes or no).

bool isFlutterFun = true;
print(isFlutterFun);

5. List

List is used to store multiple values in a single variable (like an array).

List fruits = ["Apple", "Banana", "Orange"];
print(fruits);

6. Map

Map is a collection of key-value pairs.

Map user = {
  "name": "Rohan",
  "city": "Delhi"
};
print(user);

7. var and dynamic

var is used when you want Dart to automatically detect the type.
dynamic allows changing the type of value at runtime.

var city = "Mumbai"; // inferred as String
city = "Pune";

dynamic item = "Book";
item = 100; // no error, type changed to int
print(item);

8. Typed vs Untyped List

In Dart, you can define a list with or without a specific type:

🔸 Untyped List

This list allows storing any data type. Not safe for large projects.

List fruits = ["Apple", "Banana", "Orange"];
fruits.add(123); // No error, but not type-safe
print(fruits);

🔹 Typed List

This list is strictly typed. Only specific types (like String) are allowed.

List<String> fruits = ["Apple", "Banana", "Orange"];
fruits.add("Mango"); // OK
fruits.add(123); // ❌ Error: int is not a String
print(fruits);

📝 Why Typed Lists?

• Type Safety: Prevents adding wrong data types
• Clean Code: Easier to maintain and debug
• Editor Support: Autocomplete and suggestions work better

📊 Comparison Table

✅ Tip: Always use List<Type> for better safety and cleaner code.