Check out example codes for "map c++". It will help you in understanding the concepts better.

Code Example 1

#include <iostream>
#include <string>
#include <map>

using std::string;
using std::map;

int main() {
	// A new map
  	map<string, int> myMap {
		{"one", 1},
    	{"two", 2},
    	{"three", 3}
  	};

  	// Print map contents (C++11 or higher)
  	for (auto& iter: myMap) {
    	std::cout << iter.first << ": " << iter.second << std::endl;  
  	}
}

Code Example 2

#include <iostream> 
#include <iterator> 
#include <map> 
  
using namespace std; 
  
int main() 
{ 
  
    // empty map container 
    map<int, int> gquiz1; 
  
    // insert elements in random order 
    gquiz1.insert(pair<int, int>(1, 40)); 
    gquiz1.insert(pair<int, int>(2, 30)); 
    gquiz1.insert(pair<int, int>(3, 60)); 
    gquiz1.insert(pair<int, int>(4, 20)); 
    gquiz1.insert(pair<int, int>(5, 50)); 
    gquiz1.insert(pair<int, int>(6, 50)); 
    gquiz1.insert(pair<int, int>(7, 10)); 
  
    // printing map gquiz1 
    map<int, int>::iterator itr; 
    cout << "\nThe map gquiz1 is : \n"; 
    cout << "\tKEY\tELEMENT\n"; 
    for (itr = gquiz1.begin(); itr != gquiz1.end(); ++itr) { 
        cout << '\t' << itr->first 
             << '\t' << itr->second << '\n'; 
    } 
    cout << endl; 
  
    // assigning the elements from gquiz1 to gquiz2 
    map<int, int> gquiz2(gquiz1.begin(), gquiz1.end()); 
  
    // print all elements of the map gquiz2 
    cout << "\nThe map gquiz2 after"
         << " assign from gquiz1 is : \n"; 
    cout << "\tKEY\tELEMENT\n"; 
    for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) { 
        cout << '\t' << itr->first 
             << '\t' << itr->second << '\n'; 
    } 
    cout << endl; 
  
    // remove all elements up to 
    // element with key=3 in gquiz2 
    cout << "\ngquiz2 after removal of"
            " elements less than key=3 : \n"; 
    cout << "\tKEY\tELEMENT\n"; 
    gquiz2.erase(gquiz2.begin(), gquiz2.find(3)); 
    for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) { 
        cout << '\t' << itr->first 
             << '\t' << itr->second << '\n'; 
    } 
  
    // remove all elements with key = 4 
    int num; 
    num = gquiz2.erase(4); 
    cout << "\ngquiz2.erase(4) : "; 
    cout << num << " removed \n"; 
    cout << "\tKEY\tELEMENT\n"; 
    for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) { 
        cout << '\t' << itr->first 
             << '\t' << itr->second << '\n'; 
    } 
  
    cout << endl; 
  
    // lower bound and upper bound for map gquiz1 key = 5 
    cout << "gquiz1.lower_bound(5) : "
         << "\tKEY = "; 
    cout << gquiz1.lower_bound(5)->first << '\t'; 
    cout << "\tELEMENT = "
         << gquiz1.lower_bound(5)->second << endl; 
    cout << "gquiz1.upper_bound(5) : "
         << "\tKEY = "; 
    cout << gquiz1.upper_bound(5)->first << '\t'; 
    cout << "\tELEMENT = "
         << gquiz1.upper_bound(5)->second << endl; 
  
    return 0; 
}

Code Example 3

# Python program to demonstrate working 
# of map. 
  
# Return double of n 
def addition(n): 
    return n + n 
  
# We double all numbers using map() 
numbers = (1, 2, 3, 4) 
result = map(addition, numbers) 
print(list(result))

Code Example 4

//assuming your variables are called : variables_
#include <map>
#include <string>

std::map<int, std::string> map_;
map_[1] = "mercury";
map_[2] = "mars";
map_.insert(std::make_pair(3, "earth"));
//either synthax works to declare a new entry

return map_[2]; //here, map_[2] will return "mars"

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