C ++ Memory Management: New, Delete and Smart hands master

introduction

The memory management in C ++ is a critical ability for developers who want to write an efficient, flawless code. In contrast to languages ​​with automatic garbage collection, C ++ programmers offer direct control over the memory assignment and cladding, which can lead to a powerful performance, but also risks such as memory leaks. This blog immerses in the C ++ memory management and focuses on the traditional new And delete Operators and the modern, safer alternative: smart pointer introduced in C ++ 11. Regardless of whether you are a beginner or an experienced coder, you learn how to manage memory effectively and avoid frequent pitfalls.

Understanding the memory management in C ++

The memory management in C ++ includes the assignment and output of memory for the objects of your program. C ++ uses two primary memory regions:

• stack: Automatically managed, used for local variables with a fixed service life.
• heap: Manually managed and used for the dynamic memory assignment new And delete.

The HEAP memory is powerful, but susceptible to problems such as:

• Memory leak: Forget to end the memory.
• Pointer dangle: Access to memory after it has been freed.

Effective C ++ spemor management ensures that your program will be carried out efficiently without wasting or overthrowing resources.

Traditional memory management: new and delete

The new operator

The new The operator assigns the memory to the heap and gives back a pointer. It is used for dynamic objects that go beyond their scope.

syntax:

CPP

Type* PTR = new type; // individual object

Type* Arr = new type (size); // array

Example:

CPP

int* num = new int (42); // assign an integer

int* arr = new int (10); // assign a number of 10 integers

The delete operator

The delete The operator drives the memory and prevents leaks.

syntax:

CPP

Delete PTR; // individual object

Delete () Arr; // array

Example:

CPP

Delete num; // free single integer

Delete () Arr; // free array

Frequent pitfalls

use new And delete Manually can be:

• Memory leak: Forget delete.
• Pointer dangle: Use a pointer afterwards delete.
• Non -matching operators: Use delete instead of delete() For arrays.

These problems make raw timers risky, especially in complex programs.

Introduction to intelligent hands

Smart Pointers, introduced in C ++ 11, automate memory management and reduce errors. They wrap up raw newspaper and automatically process the disallocation with Raii (resource recording is initialization). The C ++ standard library offers three most important intelligent hands:

• Std :: Unique_Ptr
• Std :: shared_ptr
• Std :: WEW_PTR

Intelligent hands improve the safety and readability of the code and make it a cornerstone of the modern C ++ programming.

Types of intelligent hands

1. STD :: unique_ptr

Std :: Unique_Ptr Represents the exclusive property of a resource. Only one Unique_Ptr Can point out an object and the memory is automatically processed when it starts out of the circumference.

Application: Manage a single resource, like a dynamically assigned object.

Example:

CPP

#contain

Std :: Unique_Ptr PTR = std :: make_unique(42);

// no need to call delete; PTR becomes free

2. STD :: shared_ptr

Std :: shared_ptr Enables several pointers to share the property of a resource. It uses the reference count to follow how many Shared_ptrS Point to the object to do it when the number reaches zero.

Application: Share of resources across several objects.

Example:

CPP

#contain

Std :: shared_ptr PTR1 = std :: make_hared(42);

Std :: shared_ptr PTR2 = PTR1; // both point to the same integer

// memory frees when both PTR1 and PTR2 have no scope

3 .. Std :: WEW_PTR

Std :: WEW_PTR Offers a non -owned reference to A Shared_ptr-Manned object. It does not affect the reference number and is used to break circular references.

Application: Prevent memory leaks in cyclical data structures.

Example:

CPP

#contain

Std :: shared_ptr sp = std :: make_hared(42);

Std :: WEW_PTR WP = SP; // weak reference on SP

Note on STD :: Auto_PTR

Std :: Auto_PTR (Pre-C ++ 11) is out of date due to the uncertain behavior. Always use Std :: Unique_Ptr instead.

Best practice for memory management in C ++

To write robust C ++ code, follow the following guidelines:

• Prefer intelligent hands: Use Std :: Unique_Ptr For individual owners and Std :: shared_ptr For common resources.
• Minimize raw hands: Avoid new And delete Unless it is absolutely necessary.
• Use Raii: Lever of the Raii principle of C ++ to bind the resource management to object life.
• Choose the right intelligent pointer:
  • Unique_Ptr For exclusive property.
  • Shared_ptr for common property.
  • WACK_PTR To avoid circular references.
• Avoid mixing hands: Do not use raw hands with intelligent hands to prevent confusion.

Practical example: Comparison of raw hands and intelligent hands

Let us compare the memory management with RAW devices and intelligent hands.

Rohe pointer:

CPP

#contain

void riskyfunction () {

int* ptr = new int (42);

Std :: Cout << *PTR << STD :: ENDL;

// forgotten call to extinguish; Storage leak!

}

Smart hands:

CPP

#contain

#contain

void safety () {

Std :: Unique_Ptr PTR = std :: make_unique(42);

Std :: Cout << *PTR << STD :: ENDL;

// no deletion required; Storage automatically freed

}

The intelligent pointer version is more secure, more readable and eliminates the risk of LECKS.

Diploma

Mastering C ++ memory management is of essential importance for writing more efficient, reliable programs. While new And delete Offer a fine -grained control, they are more prone to errors. Smart hands like Std :: Unique_PtrPresent Std :: shared_ptrAnd Std :: WEW_PTR Simplify the memory management and make up with modern C ++ practices. Integrate Smart hands into your projects to improve the security and maintainability of the code. Have questions or tips? Share them in the comments below!

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