How does the use of dynamic, var, and Object differ in defining data types in a programming language?

In the Dart language (used in Flutter), dynamic, var, and Object have different characteristics:

• var — a variable with an implicit type, which is determined at initialization and then fixed. For example:

var x = 10; // x is int
x = 20; // OK
x = 'string'; // Compilation error

• dynamic — a variable whose type is checked at runtime; the compiler does not check types during assignment and method calls:

dynamic y = 10;
y = 'string'; // OK
print(y.length); // Error will only occur at runtime if length does not exist

• Object — the base class for all types; a variable of type Object can contain any object, but to call specific methods, type casting is necessary:

Object z = 10;
// z.length; // Compilation error
if (z is String) {
  print(z.length); // OK after type check
}

Summary:

• var — type is fixed at initialization.
• dynamic — disables type checking, flexible but less safe.
• Object — base type, requires explicit casting for specific operations.