String Manipulation (string)

This lesson covers basic string manipulation using std::string. It's for anyone searching "C++ string manipulation."

std::string comes with handy features — length() to get the length, substr() to extract a substring, and the + operator to concatenate strings.

The example checks the character count with message.length(), and extracts the first 5 characters with message.substr(0, 5).

A common early mistake is how character counting works with multi-byte characters. std::string's length() returns a byte count, so a single non-ASCII character can be counted as multiple bytes.

In real projects, string manipulation — validating user input, formatting a log line, and more — is essential to nearly every program.

📖 Reference code

#include <iostream>
#include <string>

int main() {
    std::string message = "Hello, C++!";
    std::cout << "Length (bytes): " << message.length() << std::endl;
    std::cout << "First 5 characters: " << message.substr(0, 5) << std::endl;
    return 0;
}

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run C++ directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).