std::string
- C++ course
- Beginner
- Lesson 16/116
- 4 min
Learn to store text with std::string.
std::string
std::string is the type for holding text. With std::string name = "Alice"; you can store text of any length. To use std::string you include the #include <string> header (most of the time <iostream> pulls it in indirectly, but writing it explicitly is safer).
std::string is safer and more convenient than C-style character arrays (char[]): it manages the length automatically and does not leak memory.
You can concatenate two strings with +: std::string full = first + " " + last;. This makes text operations easy.
string operations
Common operations with std::string:
- Length:
name.length()orname.size()gives the character count - Concatenation:
+joins two strings side by side - Access:
name[0]gives the first character - Comparison:
==checks whether two strings are the same
Example: std::string greeting = "Hello " + name; builds a greeting string. greeting.length() gives the number of characters.
Practice Concatenate strings and print
Add the #include <string> header. Inside main, declare two std::string variables: firstName with value "Alice" and lastName with value "Smith". Declare a third std::string named fullName as firstName + " " + lastName. Print fullName with std::cout using std::endl.
Starter code
#include <iostream>
int main() {
// Declare firstName and lastName
// Define fullName by concatenation
// Print fullName with std::cout
return 0;
}Sample solution
#include <iostream>
#include <string>
int main() {
// Declare firstName and lastName
std::string firstName = "Alice";
std::string lastName = "Smith";
// Define fullName by concatenation
std::string fullName = firstName + " " + lastName;
// Print fullName with std::cout
std::cout << fullName << std::endl;
return 0;
}Expected output
Alice Smith
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which header is included to use std::string?
- <vector>
- <string> Correct answer
- <map>
- <list>
Explanation: std::string is defined in the <string> header.
2 Match string operations
| Term | Meaning |
|---|---|
+ |
Concatenation |
length() |
Character count |
[0] |
First character |
== |
Equality comparison |
3 String declaration
____ name = "Alice";std::string name = "Alice";Explanation: Text is stored in std::string.