[c++] How to use range-based for() loop with std::map?

Each element of the container is a map<K, V>::value_type, which is a typedef for std::pair<const K, V>. Consequently, in C++17 or higher, you can write

for (auto& [key, value]: myMap) {
    std::cout << key << " has value " << value << std::endl;
}

or as

for (const auto& [key, value]: myMap) {
    std::cout << key << " has value " << value << std::endl;
}

if you don't plan on modifying the values.

In C++11 and C++14, you can use enhanced for loops to extract out each pair on its own, then manually extract the keys and values:

for (const auto& kv : myMap) {
    std::cout << kv.first << " has value " << kv.second << std::endl;
}

You could also consider marking the kv variable const if you want a read-only view of the values.

Examples related to c++

Method Call Chaining; returning a pointer vs a reference? How can I tell if an algorithm is efficient? Difference between opening a file in binary vs text How can compare-and-swap be used for a wait-free mutual exclusion for any shared data structure? Install Qt on Ubuntu #include errors detected in vscode Cannot open include file: 'stdio.h' - Visual Studio Community 2017 - C++ Error How to fix the error "Windows SDK version 8.1" was not found? Visual Studio 2017 errors on standard headers How do I check if a Key is pressed on C++

Examples related to c++11

Remove from the beginning of std::vector Converting std::__cxx11::string to std::string What exactly is std::atomic? C++ How do I convert a std::chrono::time_point to long and back Passing capturing lambda as function pointer undefined reference to 'std::cout' Is it possible to use std::string in a constexpr? How does #include <bits/stdc++.h> work in C++? error::make_unique is not a member of ‘std’ no match for ‘operator<<’ in ‘std::operator

Examples related to for-loop

List append() in for loop Prime numbers between 1 to 100 in C Programming Language Get current index from foreach loop how to loop through each row of dataFrame in pyspark TypeScript for ... of with index / key? Is there a way in Pandas to use previous row value in dataframe.apply when previous value is also calculated in the apply? Python for and if on one line R for loop skip to next iteration ifelse How to append rows in a pandas dataframe in a for loop? What is the difference between ( for... in ) and ( for... of ) statements?

Examples related to dictionary

JS map return object python JSON object must be str, bytes or bytearray, not 'dict Python update a key in dict if it doesn't exist How to update the value of a key in a dictionary in Python? How to map an array of objects in React C# Dictionary get item by index Are dictionaries ordered in Python 3.6+? Split / Explode a column of dictionaries into separate columns with pandas Writing a dictionary to a text file? enumerate() for dictionary in python