C++ · Chapter 11 of 49
C++ Strings
The `std::string` class (from `<string>`) represents text and supports concatenation with `+`, comparison with `==`, and indexing with `[]`. It automatically manages memory, growing as needed.
Strings are zero-indexed, so `s[0]` is the first character. C++ also has C-style character arrays, but std::string is safer and easier for most tasks.
Creating and combining strings
You can concatenate strings with `+`, or append with `+=`. Comparing two strings with `==` checks their content, not their memory address.
Accessing characters
`s[i]` or `s.at(i)` returns the character at index i. `.at()` throws an exception on out-of-range access, while `[]` has undefined behaviour.
Example 1 (cpp)
std::string first = "Hello";
std::string full = first + ", World!";
std::cout << full;Output
Hello, World!+ concatenates two strings.
Example 2 (cpp)
std::string s = "cpp";
std::cout << s[0] << s.length();Output
c3Indexing gives a single character; length() gives the size.
Key points
- std::string needs #include <string>.
- + concatenates; += appends in place.
- Strings are zero-indexed via [] or .at().
- == compares string content.
💡 Note: .at() is safer than [] because it throws std::out_of_range instead of undefined behaviour.