Introdunction of Dart Functions
Dart Functions are self-contained modules of code that perform a specific task. They can be used to execute code, return a value, or both, allowing for modular, reusable, and maintainable code. Dart provides a flexible syntax for defining functions, supporting features like optional parameters, default values, and arrow syntax for concise expressions. Here’s a detailed overview of how functions work in Dart, complete with examples.
1. Basic Function
A basic dart functions can perform a task and return a result. Functions are defined using the void keyword when no value is returned.
void greet() {
print('Hello, World!');
}
greet(); // Output: Hello, World!
2. Function with Parameters
Functions can take parameters, which are specified during the function call.
void greet(String name) {
print('Hello, $name!');
}
greet('Alice'); // Output: Hello, Alice!
3. Function with Return Value
Functions can return a value. The type of the return value is specified before the function name.
String getGreeting(String name) {
return 'Hello, $name!';
}
print(getGreeting('Bob')); // Output: Hello, Bob!
4. Arrow Syntax
For functions that contain a single expression, Dart offers a concise syntax using the arrow (=>). This is equivalent to { return expr; }.
String getGreeting(String name) => 'Hello, $name!';
print(getGreeting('Charlie')); // Output: Hello, Charlie!
5. Optional and Named Parameters
Dart supports optional positional and named parameters, which can have default values.
void greet(String firstName, {String lastName = '', int age = 30}) {
print('Hello, $firstName $lastName! Age: $age');
}
greet('Alice', lastName: 'Smith'); // Output: Hello, Alice Smith! Age: 30
6. Anonymous Functions
Often used for callbacks or as arguments to higher-order functions. These do not have names and are defined directly within other functions.
var names = ['Alice', 'Bob', 'Charlie'];
names.forEach((name) {
print(name);
});
Conclusion Dart Functions
Understanding and using functions effectively in Dart allows you to write cleaner, more efficient, and maintainable code. Functions help break down complex problems into simpler, manageable tasks, which is essential for large-scale application development in Flutter.
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Posted by Hussam HM
