exam3 from Pascal Chibukem

exam3/exam3/.gitignore

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+# https://dart.dev/guides/libraries/private-files
+# Created by `dart pub`
+.dart_tool/

exam3/exam3/CHANGELOG.md

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+## 1.0.0
+
+- Initial version.

exam3/exam3/README.md

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+A sample command-line application with an entrypoint in `bin/`, library code
+in `lib/`, and example unit test in `test/`.

exam3/exam3/analysis_options.yaml

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+# This file configures the static analysis results for your project (errors,
+# warnings, and lints).
+#
+# This enables the 'recommended' set of lints from `package:lints`.
+# This set helps identify many issues that may lead to problems when running
+# or consuming Dart code, and enforces writing Dart using a single, idiomatic
+# style and format.
+#
+# If you want a smaller set of lints you can change this to specify
+# 'package:lints/core.yaml'. These are just the most critical lints
+# (the recommended set includes the core lints).
+# The core lints are also what is used by pub.dev for scoring packages.
+
+include: package:lints/recommended.yaml
+
+# Uncomment the following section to specify additional rules.
+
+# linter:
+#   rules:
+#     - camel_case_types
+
+# analyzer:
+#   exclude:
+#     - path/to/excluded/files/**
+
+# For more information about the core and recommended set of lints, see
+# https://dart.dev/go/core-lints
+
+# For additional information about configuring this file, see
+# https://dart.dev/guides/language/analysis-options

exam3/exam3/bin/exam3.dart

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+import 'package:exam3/exam3.dart' as exam3;
+
+void main() async {
+  print(addInt(3, 5));
+
+//calling un named function in 4b
+  print(multiply(4, 5)); // Output: 20
+
+  // 7
+  greet('Alice', 30);
+  //b
+  greet2(name2: 'Alice', age2: 30);
+
+  //9
+  greeting(name: 'Alice');
+
+  //10
+  greets('Bob', 'Hello');
+
+  //11
+  printMessage('Hello, World!');
+
+  //12
+  outerFunction();
+
+  //13
+  // Define a function to add two numbers
+  int add(int a, int b) {
+    return a + b;
+  }
+
+  // Pass the 'add' function as a parameter to the higher-order function
+  higherOrderFunction(3, 5, add); // Output: 8
+
+  //15
+  greet3('Alice'); // Output: Hello, Alice!
+  greet3('');
+
+  //17
+  print('Starting...');
+  myAsyncFunction(); // Calling the asynchronous function
+  print('Continuing with other tasks...');
+
+  //18
+  print('Fetching data...');
+
+  // Call the asynchronous function and wait for the result
+  int result = await fetchData();
+
+  print('Data fetched: $result');
+
+  //19
+  //myFunction();
+}
+
+//1. function in dart just like every other programming language is a block of re
+//reusable code meant to perform a particular task, as shown below.
+// Named function
+int addInt(int a, int b) {
+  return a + b;
+}
+
+//2. function is declared by specifying the return type and the the fn name,
+// a closed brackets for the parameter if required and curly brackets for body.
+int name(parameters) {
+  return parameters;
+}
+//3. main()fn is where execution of programme start without it, programme can not run.
+
+//4. different between named and un-named function
+int subtract(int a, int b) {
+  //named function
+  return a - b;
+}
+
+var multiply = (int a, int b) {
+  //un-named function which can be called anywhere
+  return a * b;
+};
+// calling un named fn
+
+//5.return type refers to the data type a fn will return after execution.
+
+double myProducts(int a, int b) {
+  // Function body
+  // Optionally, return a value of returnType
+  return (2.7 * 8.1);
+}
+
+//6. parameter is passed by including it in the parenthesis after fn name
+String fullName(String firstName, surName) {
+  return fullName(firstName, surName);
+}
+
+//7. positional parameter
+void greet(String name, int age) {
+  print('Hello, $name! You are $age years old.');
+}
+
+//named parameter
+void greet2({String? name2, int? age2}) {
+  print('Hello, $name2 You are $age2 years old.');
+}
+
+//8 arrow is used to write fn with single expression as shown below
+int square(int x) => x * x;
+
+//9 how default parameter is used
+void greeting({String name = 'World'}) {
+  print('Hello, $name!');
+}
+
+//10 optional parameter
+void greets(String name, [String prefix = 'Hello']) {
+  print('$prefix, $name!');
+}
+
+//11 void used to indicate function with no return, rather void functions.
+void printMessage(String message) {
+  print(message);
+}
+
+//12 nested function
+void outerFunction() {
+  print('Outer function');
+
+  void innerFunction() {
+    print('Inner function');
+  }
+
+  innerFunction();
+}
+
+//13 higher order function
+void higherOrderFunction(int x, int y, Function(int, int) operation) {
+  print(operation(x, y));
+}
+
+//15 how to use return key word in dart
+// Function definition
+void greet3(String name) {
+  if (name.isEmpty) {
+    print('Name is empty, cannot proceed.');
+    return; // Exit the function early
+  }
+  print('Hello, $name!');
+}
+
+//16 function signature, ma
+int add(int a, int b) {
+  return a + b;
+}
+
+//17  making function in dart asynchronous
+Future<void> myAsyncFunction() async {
+  // Asynchronous code that might take time to execute
+  await Future.delayed(Duration(seconds: 1));
+  print('Async operation complete');
+}
+
+//18 use of async , await and future
+// Asynchronous function that simulates fetching data from an API
+Future<int> fetchData() async {
+  // Simulate a delay of 2 seconds (asynchronous operation)
+  await Future.delayed(Duration(seconds: 2));
+
+  // Return a value after the delay
+  return 42;
+}
+
+//19 calling function defined in other dart file involves importing the file into the file in which you want call it,
+// and then call it as i did in the main method.

exam3/exam3/lib/exam3.dart

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+int calculate() {
+  return 6 * 7;
+}