std::map::contains(3)

💅 std::map::contains(3) 💅

C++ Standard Libary, bestie — yes, that's the manual name, typo and all. Welcome to the page.

🌸 NAME 🌸

std::map::contains — literally std::map::contains. That's the whole name, no cap.

🦋 Synopsis 🦋

Okay so here's the synopsis, and yes the code formatting is part of the vibe:

bool contains( const Key& key ) const; (1) (since C++20)
template< class K >                    (2) (since C++20)
bool contains( const K& x ) const;

1. Checks if there is an element with key equivalent to key in the container.
2. Checks if there is an element with key that compares equivalent to the value x. This overload participates in overload resolution only if the qualified-id Compare::is_transparent is valid and denotes a type. It allows calling this function without constructing an instance of Key.

🎀 Parameters 🎀

• key — key value of the element to search for.
• x — a value of any type that can be transparently compared with a key.

✨ Return value ✨

true if there is such an element, otherwise false. That's it, bestie.

🔥 Complexity 🔥

Logarithmic in the size of the container. Slay, but make it logarithmic.

🍓 Example 🍓

Obsessed with this little demo? Same:

// Run this code

#include <iostream>
#include <map>

int main()
{
    std::map<int, char> example{{1, 'a'}, {2, 'b'}};

    for (int x : {2, 5})
        if (example.contains(x))
            std::cout << x << ": Found\n";
        else
            std::cout << x << ": Not found\n";
}

🌈 Output 🌈

2: Found
5: Not found

👑 See also 👑

• find — finds element with specific key (public member function)
• count — returns the number of elements matching specific key (public member function)
• equal_range — returns range of elements matching a specific key (public member function)

Okay bye, bestie — source/version is http://cppreference.com, dated 2024.06.10, and the page is std::map::contains(3) 💖