How do I use heterogeneous lookup with std::multimap?

In C++, a `std::multimap` is an associative container that allows for the storage of key-value pairs, where multiple keys can have the same value. Heterogeneous lookup refers to the ability to search for elements using different types of keys. In the case of `std::multimap`, you can perform lookups with various types of keys as long as they are comparable to the key type of the multimap.

For example, you may have a `std::multimap` that uses `std::string` keys and want to perform lookups using `const char*` or similar types. C++ allows this flexibility through implicit type conversions.

Example of Heterogeneous Lookup in std::multimap

#include <iostream> #include <map> #include <string> int main() { std::multimap<:string int> mmap; mmap.insert({"apple", 1}); mmap.insert({"banana", 2}); mmap.insert({"apple", 3}); // Heterogeneous lookup using const char* auto range = mmap.equal_range("apple"); // using std::string std::cout << "Values for 'apple':" << std::endl; for(auto it = range.first; it != range.second; ++it) { std::cout << it->second << std::endl; } return 0; }

std::multimap heterogeneous lookup C++ C++ multimap example associative containers implicit type conversion

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