Converting C-style Strings to std::string

Converting a C-style string to a std::string is straightforward in C++. The std::string class provides a constructor that accepts a C-style string (const char*) as an argument. This constructor efficiently creates a std::string object from the C-style string.

Here's a simple example:

1#include <iostream>
2#include <string>
3
4int main() {
5  const char* cString{"Hello, World!"};
6  std::string stdString{cString};  
7
8  std::cout << "C-style string: "
9    << cString << '\n';
10  std::cout << "std::string: "
11    << stdString << '\n';
12}

1C-style string: Hello, World!
2std::string: Hello, World!

This conversion is efficient because std::string is designed to handle such conversions internally. It allocates the necessary memory and copies the characters from the C-style string.

If you need to convert multiple C-style strings or perform the conversion frequently, you might want to consider using std::string_view as an intermediate step. std::string_view provides a lightweight, non-owning reference to a string, which can be useful when you don't need to modify the string:

1#include <iostream>
2#include <string>
3#include <string_view>
4
5void processString(std::string_view sv) {
6  std::string stdString{sv};  
7  std::cout << "Processed string: " << stdString;
8}
9
10int main() {
11  const char* cString{"Hello, C++!"};
12  processString(cString);
13}

1Processed string: Hello, C++!

Using std::string_view can be more efficient in scenarios where you're passing strings around without modifying them, as it avoids unnecessary copying.

Remember, while this conversion is generally efficient, if you're working in a performance-critical section of code and converting many strings, it's worth profiling your application to ensure this isn't becoming a bottleneck.