fix warnings

02_built_in_data_types.dart

@@ -1,27 +1,27 @@
+// ignore_for_file: unused_local_variable
 
 void main(List<String> arguments) {
+  // Numbers: int
+  int score = 23;
+  var count = 23; // It is inferred as integer automatically by compiler
+  int hexValue = 0xEADEBAEE;
 
-	// Numbers: int
-	int score = 23;
-	var count = 23;     // It is inferred as integer automatically by compiler
-	int hexValue = 0xEADEBAEE;
+  // Numbers: double
+  double percentage = 93.4;
+  var percent = 82.533;
+  double exponents = 1.42e5;
 
-	// Numbers: double
-	double percentage = 93.4;
-	var percent = 82.533;
-	double exponents = 1.42e5; 
+  // Strings
+  String name = "Henry";
+  var company = "Google";
 
-	// Strings
-	String name = "Henry";
-	var company = "Google";
+  // Boolean
+  bool isValid = true;
+  var isAlive = false;
 
-	// Boolean
-	bool isValid = true;
-	var isAlive = false;
+  print(score);
+  print(exponents);
 
-	print(score);
-	print(exponents);
-
-	// NOTE: All data types in Dart are Objects.
-	// Therefore, their initial value is by default 'null'
+  // NOTE: All data types in Dart are Objects.
+  // Therefore, their initial value is by default 'null'
 }

03_string_and_string_interpolation.dart

@@ -1,32 +1,30 @@
+// ignore_for_file: unused_local_variable
 
 void main() {
+  // Literals
+  var isCool = true;
+  int x = 2;
+  "John";
+  4.5;
 
-	// Literals
-	var isCool = true;
-	int x = 2;
-	"John";
-	4.5;
+  // Various ways to define String Literals in Dart
+  String s1 = 'Single';
+  String s2 = "Double";
+  String s3 = 'It\'s easy';
+  String s4 = "It's easy";
 
-	// Various ways to define String Literals in Dart
-	String s1 = 'Single';
-	String s2 = "Double";
-	String s3 = 'It\'s easy';
-	String s4 = "It's easy";
+  String s5 = 'This is going to be a very long String. '
+      'This is just a sample String demo in Dart Programming Language';
 
-	String s5 = 'This is going to be a very long String. '
-			'This is just a sample String demo in Dart Programming Language';
+  // String Interpolation : Use ["My name is $name"] instead of ["My name is " + name]
+  String name = "Kevin";
 
+  print("My name is $name");
+  print("The number of characters in String Kevin is ${name.length}");
 
-	// String Interpolation : Use ["My name is $name"] instead of ["My name is " + name]
-	String name = "Kevin";
+  int l = 20;
+  int b = 10;
 
-	print("My name is $name");
-	print("The number of characters in String Kevin is ${name.length}");
-
-
-	int l = 20;
-	int b = 10;
-
-	print("The sum of $l and $b is ${l + b}");
-	print("The area of rectangle with length $l and breadth $b is ${l * b}");
+  print("The sum of $l and $b is ${l + b}");
+  print("The area of rectangle with length $l and breadth $b is ${l * b}");
 }

04_constants.dart

@@ -1,19 +1,18 @@
+// ignore_for_file: unused_local_variable
 
 void main() {
+  // final
+  final cityName = 'Mumbai';
+  //	name = 'Peter';     // Throws an error
 
-	// final
-	final cityName = 'Mumbai';
-	//	name = 'Peter';     // Throws an error
+  final String countryName = 'India';
 
-	final String countryName = 'India';
-
-	// const
-	const PI = 3.14;
-	const double gravity = 9.8;
+  // const
+  const PI = 3.14;
+  const double gravity = 9.8;
 }
 
 class Circle {
-
-	final color = 'Red';
-	static const PI = 3.14;
+  final color = 'Red';
+  static const PI = 3.14;
 }

12_continue_keyword.dart

@@ -1,17 +1,17 @@
+// ignore_for_file: unused_label
 
 void main() {
+  // CONTINUE keyword
+  // Using Labels
 
-	// CONTINUE keyword
-	// Using Labels
-
-	myLoop: for (int i = 1; i <= 3; i++) {
-
-		myInnerLoop: for (int j = 1; j <= 3; j++) {
-
-			if (i == 2 && j == 2) {
-				continue myLoop;
-			}
-			print("$i  $j");
-		}
-	}
+  myLoop:
+  for (int i = 1; i <= 3; i++) {
+    myInnerLoop:
+    for (int j = 1; j <= 3; j++) {
+      if (i == 2 && j == 2) {
+        continue myLoop;
+      }
+      print("$i  $j");
+    }
+  }
 }