Remove element from the map container in C++
By Ayush TripathiHello guys, In this tutorial, we will learn how to remove an element from the map container in C++.
Suppose we want to store the name and roll number of each student, then the map will look like below:
<4,Ram> <6,Shyam> <10,faiz> <16,Harpreet> <12,Shivam>
Creating map
map<data_type1,data_type2> map_name;
Inserting in map
We use built-in insert() function to insert an element in map.
map_name.insert({key,value});#include <iostream>
#include<map>
using namespace std;
int main() {
map<int,string> mp; //declaring map
mp.insert({1,"INDIA"}); //inserting in map
mp.insert({2,"CHINA"}); //inserting in map
mp.insert({3,"USA"}); //inserting in map
mp.insert({4,"RUSSIA"}); //inserting in map
for(auto i=mp.begin();i!=mp.end();i++)
{
cout << i->first <<" "<<i->second<<endl; //i->first will print key.
//i->second will print value.
}
return 0;
}Output
1 INDIA 2 CHINA 3 USA 4 RUSSIA
C++ program to remove element from the map container
erase(key)- It will delete a key and its value. The return type of this function is an integer. It returns how many entries deleted.
#include <iostream>
#include<map>
using namespace std;
int main() {
map<int,string> mp; //declaring map
mp.insert({1,"INDIA"}); //inserting in map
mp.insert({2,"CHINA"}); //inserting in map
mp.insert({3,"USA"}); //inserting in map
mp.insert({4,"RUSSIA"}); //inserting in map
for(auto i=mp.begin();i!=mp.end();i++)
{
cout << i->first <<" "<<i->second<<endl; //i->first will print key.
//i->second will print value.
}
int x=mp.erase(2); //calling erase fuction and deleting key 2
for(auto i=mp.begin();i!=mp.end();i++)
{
cout << i->first <<" "<<i->second<<endl; //i->first will print key.
//i->second will print value.
}
return 0;
}1 INDIA 2 CHINA 3 USA 4 RUSSIA 1 INDIA 3 USA 4 RUSSIA
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