C++ memory management mechanism principle

C++ memory management mechanism ensures that the program uses memory efficiently through memory layout (code segment, data segment, heap, stack) and memory allocation methods (stack allocation, heap allocation). Programmers need to manually release heap memory to avoid memory leaks, which can be achieved by using the delete operator or smart pointers.

C++ memory management mechanism principle

Introduction

Memory management is in C++ An important task that ensures that programs use memory efficiently while running, thus avoiding memory leaks and segfaults.

Memory layout

The memory of a C++ program is usually divided into the following areas:

• Code segment: Stored program instructions
• Data segment: Stored program data
• Heap: Dynamically allocated memory
• Stack: Memory for local variables and function calls

Memory allocation

In C++, there are two common ways to allocate memory:

1. Stack allocation

• Use variables declared by auto, int and other built-in types to allocate memory on the stack.
• Memory allocation and release on the stack is automatically managed by the compiler.

2. Heap allocation

• Use the new operator to dynamically allocate memory on the heap.
• The programmer is responsible for freeing the memory allocated on the heap using the delete operator.

Memory release

• Stack variable: When the function returns or ends, the stack memory will be automatically released.
• Heap variables: Programmers must manually free heap memory using the delete operator. If you don't do this, a memory leak will occur.

Memory Leak

Memory leak means that memory that is no longer needed is not released, resulting in a reduction in the memory available to the system. In C++, memory leaks can be avoided by:

• Always call delete explicitly for heap-allocated memory.
• Use smart pointers (such as unique_ptr and shared_ptr) to automatically manage memory.

Practical case

Consider the following C++ code:

int* p = new int; // 在堆上分配一个整数
*p = 10; // 将值 10 存储在指向的内存中

// ... 使用 p 指针 ...

delete p; // 释放堆内存

In this example, we used new operator allocates an integer on the heap. We then use the dereference operator * to store a value. After allocation, use delete to free the memory to avoid memory leaks.

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