What are the differences between std::string, std::wstring, and std::u8string?

Question

Accepted Answer

**std::string** — char. **std::wstring** — wchar_t. **std::u8string** — char8_t (UTF-8).

```cpp
#include <string>

// std::string — narrow characters (usually UTF-8)
std::string s = "Hello";
std::string utf8 = "Привет";  // UTF-8 bytes

// std::wstring — wide characters
std::wstring ws = L"Hello";
std::wstring wu = L"Привет";

// std::u8string — UTF-8 (C++20)
std::u8string u8s = u8"Привет";

// std::u16string — UTF-16
std::u16string u16s = u"Привет";

// std::u32string — UTF-32
std::u32string u32s = U"Привет";

// Size comparison
std::cout << s.size();    // Bytes in UTF-8
std::cout << ws.size();   // Number of wchar_t
std::cout << u32s.size(); // Number of code points

// Conversion
std::string from_wide(ws.begin(), ws.end());
std::wstring to_wide(s.begin(), s.end());

// Format (C++20)
std::cout << std::format("{}", s);  // Works with all
std::wcout << std::format(L"{}", ws);
```

**Recommendations:**
- Use std::string with UTF-8 for most cases.
- Use std::wstring for Windows API.
- Use std::u32string for code point operations.

C++: What are the differences between std::string, std::wstring, and std::u8string?