In-depth analysis of pointers and references in C++ to optimize memory usage

By using pointers and references, memory usage in C++ can be optimized: Pointers: store addresses of other variables and can point to different variables, saving memory, but may generate wild pointers. Reference: Aliased to another variable, always points to the same variable, does not generate wild pointers, and is suitable for function parameters. Optimizing memory usage can improve code efficiency and performance by avoiding unnecessary copies, reducing memory allocations, and saving space.

In-depth analysis of pointers and references in C++, optimizing memory usage

Pointers and referencesare C++ Powerful tools for efficiently managing memory. It is crucial to understand their characteristics and differences in order to optimize your code and avoid common mistakes.

Pointer

A pointer is a variable that stores the address of other variables. It allows you to access the variable's value indirectly, just like direct access.

Declare a pointer:

int* ptr;  // 指向 int 的指针

Access the value pointed to by the pointer:

*ptr = 10;  // 等同于 *(ptr)

Advantages:

• Allows direct manipulation of memory.
• can point to different variables.
• Save memory because the pointer itself only stores an address.

Practical case: dynamic memory allocation

Use the new operator to dynamically allocate memory and store its address in a pointer:

int* num = new int(10);  // 分配一个存储 10 的 int
*num = 20;  // 修改所指向的值
delete num;  // 释放内存

Quote

A reference is a pointer aliased to another variable. It always points to the same variable and cannot be reassigned.

Declare a reference:

int& ref = num;  // 引用变量 num

Access the value pointed to by the reference:

ref = 10;  // 等同于 num = 10

Advantages:

• As efficient as accessing variables directly.
• No wild pointers will be generated because the reference always points to a valid variable.
• can be used for function parameters, allowing the function to modify the data passed by the caller.

Practical case: passing function parameters

When using a reference as a function parameter, you can modify the value of the incoming variable:

void multiplyByTwo(int& num) {
  num *= 2;
}

Comparison of pointers and references

• Avoid unnecessary copies: Use references or pointers to pass objects instead of copying them.
• Reduce memory allocation: Use pointers to dynamically allocate memory, allocating only when needed.
• Saving space: Use pointers to store addresses of large amounts of data instead of storing the data itself.

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