Change the Value of a Key in Map in C++
To update the value of a key in the map, we can use the subscript operator [] to directly access and assign value. The key will be passed inside the [] and the assignment operator will be used to assign the new value. Keep in mind that the new value should be of the same type as the previous one.
C++ Program to Update Value of a Key in Map
C++
// C++ Program to Update Value of a Key in Map #include <iostream> #include <map> using namespace std; int main() { // creating a map map<int, string> myMap = { { 1, "One" }, { 2, "Two" } }; // Updating an existing element's value myMap[2] = "Three"; // Accessing and printing elements cout << "Map after Updating" << endl; for (auto it : myMap) { cout << "Key:" << it.first << " Value:" << it.second << endl; } return 0; } |
Output
Map after Updating Key:1 Value:One Key:2 Value:Three
Time Complexity: O(1)
Auxiliary Space: O(1)
How to Update Value of a Key in Map in C++?
In C++, a map is a data structure that stores key-value pairs. In this article, we will learn how to change the value of a key that is already present in the map container in C++.
Example
Input: map<int, string> mp = {(1, "One"), (2,"Two")} Output: map after Updation: {(1, "One"), (2, "Three")}
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