CPP

check if an element is in a map c++

if(m.contains(key))
	//true if contains

check if a key is in map c++

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

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;
}