Concept

Every Dart program starts at:

void main() {
  // code here runs first
}

Tutorial steps

1. Write this in main.dart:

void main() {
  print('Hello Dart!');
}

2. Run it.
3. Change the message and run again.

Quick rules

• Dart strings can use ' or "
• Every statement ends with ;

Practice tasks

• Print your name
• Print your favorite food
• Print 3 lines (3 print() calls)

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How code runs (execution order)

Goal

Understand top-to-bottom execution.

Tutorial

Write:

void main() {
  print('1) Start');
  print('2) Middle');
  print('3) End');
}

Run and confirm the order of output.

Practice tasks

• Make a "morning routine" log: Wake up, Brush, Breakfast
• Try rearranging lines and see how the output changes

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Comments

Goal

Learn how to write notes in code.

Types of comments

// Single line comment

/*
Multi-line comment
for bigger notes
*/

Tutorial

Add comments above your prints:

void main() {
  // This is the start of my program
  print('Hello!');
}

Practice task

Write a comment describing what your program does.

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Your first "bug" (syntax error)

Goal

Get comfortable reading errors (don't fear them).

Try this (intentionally wrong)

Remove a semicolon:

void main() {
  print('Hello')
}

What you should notice

• Error shows line number
• It complains about ; or "Expected …"

Fix it

Add the semicolon back.

Practice

Make 2 different syntax mistakes on purpose and read the errors:

• Missing )
• Missing }

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Runtime error vs syntax error

Goal

Know the difference.

Syntax error (won't run)

Code is not valid Dart. The program won't compile or run.

Runtime error (runs then crashes)

Example:

void main() {
  int a = 10;
  int b = 0;
  print(a ~/ b); // integer divide by zero
}

Practice

Change b to 2, then 1, then 0. Observe what happens.

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Mini Project — "Hello + your name"

Goal

Create a tiny program with multiple prints.

Build

void main() {
  print('Hello!');
  print('My name is Shafiul.');
  print('I am learning Dart.');
}

Upgrade ideas

• Add your city
• Add your goal (e.g., "I want to build apps")

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Mini Project - Simple calculator (hardcoded)

Goal

Do basic math and print results.

void main() {
  int a = 12;
  int b = 4;

  print('a = $a, b = $b');
  print('a + b = ${a + b}');
  print('a - b = ${a - b}');
  print('a * b = ${a * b}');
  print('a / b = ${a / b}');
}

Practice upgrades

• Change int to double
• Try ~/ (integer division)
• Try % (remainder/modulo)