What encoding methods are used when C++ functions return strings?

There are several encoding methods when the function returns a string: String literal: returns a direct string, simple and fast. Standard string (std::string): Use the std::string class for better performance. Dynamically allocate strings: Dynamically allocate character arrays and manually convert them into strings, which can be used for larger strings. Shared pointer: Use shared pointers to manage character arrays and provide memory management. The choice of encoding depends on performance, memory management, and semantic requirements. For simple strings, string literals are the best choice; for complex needs, use dynamic allocation or shared pointers.

C The encoding method when the function returns a string

In C, there are multiple encoding methods when the function returns a string , each method has its advantages and disadvantages.

1. String literal

The simplest method is to directly return a string literal, as shown below:

std::string get_name() {
  return "John Doe";
}

2. Standard string (std::string)

Another method is to use the standard string (std::string) class, as follows:

std::string get_name() {
  std::string name = "John Doe";
  return name;
}

3. Dynamically allocate string (new char[])

Dynamically allocate a character array and manually convert it to a string, as follows:

std::string get_name() {
  char* name = new char[8];  // 8 字节的字符数组
  strcpy(name, "John Doe");
  std::string result(name);
  delete[] name;
  return result;
}

4. shared_ptr

Use shared pointer (std::shared_ptr) to manage character array, as shown below:

std::string get_name() {
  auto name = std::make_shared<char[]>(8);  // 8 字节的字符数组
  strcpy(name.get(), "John Doe");
  return std::string(name.get());
}

Practical case:

Let us consider a function that returns the course name. We can use standard strings as follows:

std::string get_course_name() {
  return std::string("Data Structures and Algorithms");
}

Selection of encoding method:

When choosing an encoding method, you need to consider the following factors:

• Performance: Dynamic allocation and shared pointers are slower than string literals or standard strings.
• Memory management: Dynamic allocation and shared pointers require manual release of memory.
• Semantics: String literals are allocated at compile time, while others are allocated at runtime.

For simple strings, string literals are usually the best choice. For longer strings or situations where complex memory management is required, dynamic allocation or shared pointers can be used.

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