Update basic_part2.dart

lib/basic_part2.dart

@@ -1,7 +1,67 @@
 void basic_variables() {
 
+  print("\nDart Variables:");
+  var name = "Bobson";
+  // name = 123;
+  // Error: A value of type 'int' can't be assigned to a variable of type 'String'.
+  print(name);
+  
+  dynamic myName = "Bobson";
+  print(myName);
+  myName = 123;
+  print(myName);
+
+  int lineCount;
+  assert(lineCount == null); // default value is null
 }
 
 void basic_control_flow() {
+  print("\nDart Control Flow:");
+
+  int number = -5;
+  // If Else
+  if (number > 0) {
+    print("$number 大於 0");
+  } else if (number < 0) {
+    print("$number 小於 0");
+  } else {
+    print("$number 等於 0");
+  }
+
+  // Switch
+  switch (number > 0) {
+    case true:
+      print("$number 大於 0");
+      break;
+    default:
+      print("$number 小於等於 0");
+  }
+
+  // For loop
+  var collection = [];
+  for (var i = 0; i < 3; i++) {
+    collection.add(i);
+  }
+  print(collection);
+
+  collection.forEach((i) => print("${i+1}"));
+  print(collection.map((i) => i+1));
+
+  for (var c in collection) {
+    print(c);
+  }
+
+  // While
+  int count = 0;
+  while (count < 5) {
+    count += 1;
+    // if (count == 3) break;
+  }
+  print(count);
 
+  do {
+    count += 5;
+    print("count 加一次 5");
+  } while (count < 14);
+  print(count);
 }