Learn DART with Real Code Examples

void main() {
    int count = 0;
    bool isDark = false;

    void updateUI() {
        print('Counter: $count');
        print('Theme: ${isDark ? 'Dark' : 'Light'}');
    }

    void increment() { count++; updateUI(); }
    void decrement() { count--; updateUI(); }
    void reset() { count = 0; updateUI(); }
    void toggleTheme() { isDark = !isDark; updateUI(); }

    updateUI();
    increment();
    increment();
    toggleTheme();
    decrement();
    reset();
}

Demonstrates a simple counter with theme toggling in Dart, runnable in console or Flutter environment.

void main() {
    int count = 0;
    List<String> history = [];

    void updateUI() {
        print('Counter: $count');
        print('History: ${history.join(', ')}');
    }

    void increment() {
        count++;
        history.add('Incremented to $count');
        updateUI();
    }

    void decrement() {
        count--;
        history.add('Decremented to $count');
        updateUI();
    }

    void reset() {
        count = 0;
        history.clear();
        history.add('Counter reset');
        updateUI();
    }

    updateUI();
    increment();
    increment();
    decrement();
    reset();
}

A console-based counter that logs each increment/decrement action in a history list.

void main() {
    int count = 0;
    bool isDark = false;

    void updateUI() {
        isDark = count % 2 == 0;
        print('Counter: $count');
        print('Theme: ${isDark ? 'Dark' : 'Light'}');
    }

    void increment() { count++; updateUI(); }
    void decrement() { count--; updateUI(); }
    void reset() { count = 0; updateUI(); }

    updateUI();
    increment();
    increment();
    increment();
    decrement();
    reset();
}

Counter that switches theme based on value thresholds in Dart console app.

void main() {
    int count = 0;
    bool isDark = false;

    var updateUI = () => print('Counter: $count, Theme: ${isDark ? 'Dark' : 'Light'}');
    var increment = () { count++; updateUI(); };
    var decrement = () { count--; updateUI(); };
    var reset = () { count = 0; updateUI(); };
    var toggleTheme = () { isDark = !isDark; updateUI(); };

    updateUI();
    increment();
    toggleTheme();
    decrement();
    reset();
}

Demonstrates using Dart anonymous functions (lambdas) for counter actions and theme toggling.

void main() {
    int count = 0;
    int maxLimit = 5;

    void updateUI() => print('Counter: $count');

    void increment() {
        if(count < maxLimit) count++;
        updateUI();
    }

    void decrement() { count--; updateUI(); }
    void reset() { count = 0; updateUI(); }

    updateUI();
    increment();
    increment();
    increment();
    increment();
    increment();
    increment(); // won't exceed maxLimit
    reset();
}

A counter that stops incrementing after reaching a maximum limit.

import 'dart:async';

void main() {
    int count = 0;

    Timer.periodic(Duration(seconds: 1), (timer) {
        count++;
        print('Counter: $count');
        if(count >= 5) timer.cancel();
    });
}

Automatically increments the counter every second using Dart Timer.

import 'dart:io';

void main() {
    int count = 0;
    while(true) {
        print('Counter: $count');
        stdout.write('Enter i/d/r/q: ');
        String? input = stdin.readLineSync();
        if(input == 'i') count++;
        else if(input == 'd') count--;
        else if(input == 'r') count = 0;
        else if(input == 'q') break;
    }
}

A console-based counter that takes user input to increment, decrement, or reset.

void main() {
    int count = 0;

    void onUpdate(int value) => print('Counter: $value');

    void increment(void Function(int) callback) {
        count++;
        callback(count);
    }

    void decrement(void Function(int) callback) {
        count--;
        callback(count);
    }

    void reset(void Function(int) callback) {
        count = 0;
        callback(count);
    }

    increment(onUpdate);
    increment(onUpdate);
    decrement(onUpdate);
    reset(onUpdate);
}

Uses callback functions to handle increment, decrement, and reset events.

void main() {
    int count = 0;
    int step = 3;

    void updateUI() => print('Counter: $count');

    void increment() { count += step; updateUI(); }
    void decrement() { count -= step; updateUI(); }
    void reset() { count = 0; updateUI(); }

    updateUI();
    increment();
    decrement();
    reset();
}

A counter that can increment or decrement by a custom step value.

import 'dart:io';

void main() {
    File file = File('counter.txt');
    int count = 0;
    if(file.existsSync()) {
        count = int.parse(file.readAsStringSync());
    }

    void updateUI() {
        print('Counter: $count');
        file.writeAsStringSync(count.toString());
    }

    void increment() { count++; updateUI(); }
    void decrement() { count--; updateUI(); }
    void reset() { count = 0; updateUI(); }

    updateUI();
    increment();
    decrement();
    reset();
}

Stores counter value in a file to persist between program runs (console app).