How to Insert Pairs into a Map in C++? - Coding

In C++, maps are STL containers that store key-value pairs and maintain the element’s order according to their keys. Pairs also store the data as key values. In this article, we will discuss how to insert a pair into a map in C++.

For Example,

Input:
map<int, string> mp = {(1, "geek"), (2,"for")}
pair<int, string> pr = {3, "geeks"}

Output: // after inserting pr to mp
mp = {(1, "geek"), (2,"for"), (3, "geeks")}

Insert Pair into a Map in C++

Pairs can be inserted directly into the map container by using the std::map::insert() function. We just need to pass the said pair as an argument to this function.

C++ Program to Insert Pair into a Map

C++

// C++ program to demonstrate the insertion of pairs into 
// map using insert() function. 
  
#include <iostream> 
#include <map> 
using namespace std; 
  
int main() 
{ 
    // Step 1: Create a map with integer keys and string 
    // values. 
    map<int, string> myMap; 
  
    // Step 2: Create a pair to insert. 
  
    pair<int, string> newPair(25, "GeeksforGeeks"); 
  
    // Step 3: Insert the pair into the map using the 
    // insert() function. 
    myMap.insert(newPair); 
  
    // Iterate over the map and print each key-value pair. 
    cout << "Contents of the map:" << endl; 
    for (const auto& pair : myMap) { 
        cout << "Key: " << pair.first 
             << ", Value: " << pair.second << endl; 
    } 
  
    return 0; 
}

Output

Contents of the map:
Key: 25, Value: GeeksforGeeks

We can also use std::map::emplace() method to insert pairs into a map instead of insert().

Reffered: https://www.geeksforgeeks.org

C++

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