CPP

check if key exists in map c++

if ( m.find("f") == m.end() ) {
  // not found
} else {
  // found
}

check if a key is in map c++

if ( m.find("f") == m.end() ) {
  // not found
} else {
  // found
}

c++ check if key exists in map

if (std::map.count(key) == 0)
{
	// Not found
}
else
{
 // Found
}

c++ map key exists

#include <iostream>
#include <map>

using std::cout; using std::cin;
using std::endl; using std::map;
using std::string;

int main(){
    string key_to_find;
    std::map<string, string> lang_map = {{"j", "Julia",},
                                         {"p", "Python",},
                                         {"m", "MATLAB",},
                                         {"o", "Octave",},
                                         {"s", "Scala",},
                                         {"l", "Lua",}};

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

    cout << "Enter the key to search for: ";
    cin >> key_to_find;

    if (lang_map.find(key_to_find) != lang_map.end()) {
        cout << "Key Exists!" << endl;
    }

    return EXIT_SUCCESS;
}

check if an element exists in a map c++

#include <iostream>
#include <unordered_map>
#include <algorithm>
 
int main()
{
    std::unordered_map<char,int> m;
 
    std::string s("abcba");
    std::for_each(s.begin(), s.end(), [&m](char &c) { m[c]++; });
 
    char ch = 's';
 
    if (m.find(ch) != m.end()) {
        std::cout << "Key found";
    } else {
        std::cout << "Key not found";
    }
 
    return 0;
}

c++ map key exists

if ( !(myMap.find("key") == myMap.end()) ) {	// "key" exists	
  
} else {	// not found	
  
}