std::string

std::string is the type C++ uses for text made of more than one character. Unlike the primitives you just learned, std::string is not a primitive type — it comes from the standard library, so you need #include <string> at the top of your file to use it.

#include <iostream>
#include <string>

int main() {
    std::string name = "Ada";
    int points = 95;
    std::cout << "Hello, " + name + "!" << std::endl;
    std::cout << "Score: " << points << std::endl;
    return 0;
}

std::string comes with many useful member functions. .length() (or its twin, .size()) returns how many characters are in the string. You can also grab a single character by its position — counting from 0 — using square brackets.

std::string word = "Code";
std::cout << word.length() << std::endl; // 4
std::cout << word[0] << std::endl;        // C

To find out how many characters are in a std::string called word, you write ____.

Unlike text types in some other languages, std::string is mutable: you can change individual characters after the string is created, using square brackets on the left side of an assignment. You can also compare two strings directly with == — it compares their actual text content, not where they live in memory.

std::string word = "Cat";
word[0] = 'B';
std::cout << word << std::endl; // Bat

std::string a = "cat";
std::string b = "cat";
std::cout << (a == b) << std::endl; // 1 (true)

You can compare the text content of two std::string values directly with the == operator.

What does word[0] = 'B'; do if word currently holds "Cat"?

One last thing to keep straight: a std::string is written with double quotes ("Ada"), while a single char is written with single quotes ('A'). Mixing them up is a very common early mistake — the compiler will complain if you try to put more than one character between single quotes.