Understanding the Pair
- Computer Science Department
Understanding pair in C++
What is pair?
pair is a simple container defined in the C++ Standard Library to store a pair of values. The values can be of different types, and the pair provides a convenient way to return two values from a function or to store two related values together.
Why Use pair?
Convenience: Easily group two values together.
Flexibility: Values can be of different types.
Simplicity: Provides an easy way to return multiple values from a function.
Syntax
Here's the basic syntax for creating a std::pair:
#include <utility> // Required for std::pair
using namespace std;
pair<Type1, Type2> pairName;Type1andType2are the types of the first and second values in the pair.pairNameis the name of thestd::pairobject.
Common pair Functions
make_pair
Description: Creates a pair object with the given values.
Syntax:
pair<Type1, Type2> p = make_pair(value1, value2);Example:
#include <iostream>
#include <utility>
using namespace std;
int main() {
auto p = make_pair(10, 'A'); // Creates a pair of int and char
cout << "First: " << p.first << ", Second: " << p.second << endl;
return 0;
}Default Constructor
Description: Creates a pair object with default-initialized members.
Syntax:
Example:
Parameterized Constructor
Description: Creates a std::pair object with specified values.
Syntax:
Example:
swap
Description: Swaps the contents of two std::pair objects.
Syntax:
Example:
tie
Description: Unpacks a pair into separate variables.
Syntax:
Example:
2024 - Programming 3 / Data Structures - Author: Dr. Kevin Roark