Learn C++ Online

This lesson contains approximately 17 minutes of video content.

Introduction

What is RAII?

An example : VectorInt

Questions

QRAII, Q1

This question is ungraded.

If you "deal" with a resource that needs paired acquire/release function calls, in the lesson we advised you to:

Define function pairs that mirror fopen/fclose and new/delete.

Encapsulate that resource in an object that enforces pairing for you.

Encapsulate the resource in a namespace that enforces pairing for you.

Use new to acquire the resource; free to release it.

Practice question: try as many times as you like

QRAII, Q2

This question is ungraded.

For scoped objects, the destructor

is executed implicitly at scope exit.

is executed when the delete operator is explicitly invoked with the object's address.

is not executed at a predictable time.

must be executed explicitly within the scope in which it is used.

Practice question: try as many times as you like

QRAII, Q3

This question is ungraded.

For objects allocated on the free store, the destructor

is executed implicitly at scope exit.

is executed when the delete operator is explicitly invoked with the object's address.

is not executed at a predictable time.

must be executed explicitly within the scope in which it is used.

Practice question: try as many times as you like

QRAII, Q4

This question is ungraded.

Resource Acquisition is Initialization (RAII) is a basic technique for resource management based on scope. The key idea behind RAII is to:

ensure every resource has a paired acquire/release functions; for example, fopen/fclose.

have the programmer define a `finally` clause for every acquisition of a resource.

make the programmer explicitly release every resource.

represent a resource by a local object.

Practice question: try as many times as you like

QRAII, Q5

This question is ungraded.

The following code snippet,

class DynamicIntegerArray {
public:
  DynamicIntegerArray();
  ~DynamicIntegerArray();
private:
  unsigned int capacity = 4;
  unsigned int size = 0;
  int* array = nullptr;
};

DynamicIntegerArray::DynamicIntegerArray() {
  array = new int[capacity];
}
DynamicIntegerArray::~DynamicIntegerArray() {
  delete[] array;
}

illustrates what programming idiom?

Copy and swap

Pointer To Implementation (pImpl)

Resource Acquisition is Initialization (RAII)

Substitution failure is not an error (SFINAE)

Practice question: try as many times as you like

RAII and dynamic memory in classes (part 1)

Introduction

What is RAII?

An example : VectorInt

Questions

Q1

QRAII, Q1

Q2

QRAII, Q2

Q3

QRAII, Q3

Q4

QRAII, Q4

Q5

QRAII, Q5