📘 Keyword : final, var, and dynamic

In Dart (and Flutter), final, var, and dynamic are keywords used for variable declaration.
They control how type and value behave after a variable is created.

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1️⃣ var

• Type is inferred at compile time from the initial value.
• Once assigned, the type cannot change, but the value can.

Example:

var name = "Kulani"; // Inferred as String
name = "Sharada";    // ✅ OK
// name = 10;        // ❌ Error: int can't be assigned to String

2️⃣ final

• Value can only be set once.
• Cannot be reassigned after being initialized.
• Type can be explicitly given or inferred.

Example:

final city = "Colombo"; // Inferred as String
// city = "Kandy";      // ❌ Error: final variable can't be reassigned

final int age = 25;     // Explicit type

3️⃣ dynamic

• Type checking is disabled — can hold any type of value.
• Type can change at runtime.
• Less safe — should be used only when necessary.

Example:

dynamic data = "Hello"; // String
data = 100;             // ✅ Now an int
data = true;            // ✅ Now a bool